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96e092dc73
WL#2474 "Multi Range Read: Change the default MRR implementation to implement new MRR interface"
WL#2475 "Batched range read functions for MyISAM/InnoDb"
"Index condition pushdown for MyISAM/InnoDB"
Igor's fix from sp1r-igor@olga.mysql.com-20080330055902-07614:
There could be observed the following problems:
1. EXPLAIN did not mention pushdown conditions from on expressions in the
'extra' column. As a result if a query had no where conditions pushed
down to a table, but had on conditions pushed to this table the 'extra'
column in the EXPLAIN for the table missed 'using where'.
2. Conditions for ref access were not eliminated from on expressions
though such conditions were eliminated from the where condition.
740 lines
19 KiB
Text
740 lines
19 KiB
Text
drop table if exists t1,t2,t3;
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create table t1 (a int not null,b int not null, primary key (a)) engine=heap comment="testing heaps" avg_row_length=100 min_rows=1 max_rows=100;
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insert into t1 values(1,1),(2,2),(3,3),(4,4);
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delete from t1 where a=1 or a=0;
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show keys from t1;
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Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment
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t1 0 PRIMARY 1 a NULL 3 NULL NULL HASH
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select * from t1;
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a b
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2 2
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3 3
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4 4
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select * from t1 where a=4;
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a b
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4 4
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update t1 set b=5 where a=4;
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update t1 set b=b+1 where a>=3;
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replace t1 values (3,3);
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select * from t1;
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a b
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2 2
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3 3
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4 6
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alter table t1 add c int not null, add key (c,a);
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drop table t1;
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create table t1 (a int not null,b int not null, primary key (a)) engine=memory comment="testing heaps";
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insert into t1 values(1,1),(2,2),(3,3),(4,4);
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delete from t1 where a > 0;
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select * from t1;
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a b
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drop table t1;
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create table t1 (a int not null,b int not null, primary key (a)) engine=heap comment="testing heaps";
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insert into t1 values(1,1),(2,2),(3,3),(4,4);
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alter table t1 modify a int not null auto_increment, engine=myisam, comment="new myisam table";
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select * from t1;
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a b
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1 1
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2 2
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3 3
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4 4
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drop table t1;
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create table t1 (a int not null) engine=heap;
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insert into t1 values (869751),(736494),(226312),(802616),(728912);
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select * from t1 where a > 736494;
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a
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869751
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802616
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alter table t1 add unique uniq_id(a);
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select * from t1 where a > 736494;
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a
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869751
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802616
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select * from t1 where a = 736494;
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a
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736494
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select * from t1 where a=869751 or a=736494;
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a
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736494
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869751
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select * from t1 where a in (869751,736494,226312,802616);
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a
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226312
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736494
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802616
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869751
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alter table t1 engine=myisam;
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explain select * from t1 where a in (869751,736494,226312,802616);
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range uniq_id uniq_id 4 NULL 4 Using where; Using index
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drop table t1;
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create table t1 (x int not null, y int not null, key x (x), unique y (y))
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engine=heap;
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insert into t1 values (1,1),(2,2),(1,3),(2,4),(2,5),(2,6);
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select * from t1 where x=1;
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x y
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1 3
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1 1
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select * from t1,t1 as t2 where t1.x=t2.y;
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x y x y
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1 1 1 1
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2 2 2 2
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1 3 1 1
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2 4 2 2
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2 5 2 2
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2 6 2 2
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explain select * from t1,t1 as t2 where t1.x=t2.y;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL x NULL NULL NULL 6
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1 SIMPLE t2 eq_ref y y 4 test.t1.x 1
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drop table t1;
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create table t1 (a int) engine=heap;
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insert into t1 values(1);
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select max(a) from t1;
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max(a)
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1
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drop table t1;
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CREATE TABLE t1 ( a int not null default 0, b int not null default 0, key(a), key(b) ) ENGINE=HEAP;
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insert into t1 values(1,1),(1,2),(2,3),(1,3),(1,4),(1,5),(1,6);
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select * from t1 where a=1;
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a b
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1 6
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1 5
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1 4
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1 3
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1 2
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1 1
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insert into t1 values(1,1),(1,2),(2,3),(1,3),(1,4),(1,5),(1,6);
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select * from t1 where a=1;
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a b
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1 6
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1 5
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1 4
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1 3
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1 2
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1 1
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1 6
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1 5
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1 4
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1 3
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1 2
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1 1
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drop table t1;
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create table t1 (id int unsigned not null, primary key (id)) engine=HEAP;
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insert into t1 values(1);
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select max(id) from t1;
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max(id)
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1
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insert into t1 values(2);
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select max(id) from t1;
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max(id)
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2
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replace into t1 values(1);
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drop table t1;
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create table t1 (n int) engine=heap;
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drop table t1;
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create table t1 (n int) engine=heap;
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drop table if exists t1;
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CREATE table t1(f1 int not null,f2 char(20) not
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null,index(f2)) engine=heap;
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INSERT into t1 set f1=12,f2="bill";
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INSERT into t1 set f1=13,f2="bill";
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INSERT into t1 set f1=14,f2="bill";
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INSERT into t1 set f1=15,f2="bill";
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INSERT into t1 set f1=16,f2="ted";
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INSERT into t1 set f1=12,f2="ted";
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INSERT into t1 set f1=12,f2="ted";
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INSERT into t1 set f1=12,f2="ted";
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INSERT into t1 set f1=12,f2="ted";
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delete from t1 where f2="bill";
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select * from t1;
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f1 f2
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16 ted
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12 ted
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12 ted
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12 ted
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12 ted
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drop table t1;
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create table t1 (btn char(10) not null, key(btn)) engine=heap;
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insert into t1 values ("hello"),("hello"),("hello"),("hello"),("hello"),("a"),("b"),("c"),("d"),("e"),("f"),("g"),("h"),("i");
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explain select * from t1 where btn like "q%";
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL btn NULL NULL NULL 14 Using where
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select * from t1 where btn like "q%";
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btn
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alter table t1 add column new_col char(1) not null, add key (btn,new_col), drop key btn;
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update t1 set new_col=left(btn,1);
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explain select * from t1 where btn="a";
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL btn NULL NULL NULL 14 Using where
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explain select * from t1 where btn="a" and new_col="a";
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref btn btn 11 const,const 2 Using where
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drop table t1;
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CREATE TABLE t1 (
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a int default NULL,
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b int default NULL,
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KEY a (a),
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UNIQUE b (b)
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) engine=heap;
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INSERT INTO t1 VALUES (NULL,99),(99,NULL),(1,1),(2,2),(1,3);
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SELECT * FROM t1 WHERE a=NULL;
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a b
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explain SELECT * FROM t1 WHERE a IS NULL;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref a a 5 const 2 Using where
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SELECT * FROM t1 WHERE a<=>NULL;
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a b
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NULL 99
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SELECT * FROM t1 WHERE b=NULL;
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a b
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explain SELECT * FROM t1 WHERE b IS NULL;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref b b 5 const 1 Using where
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SELECT * FROM t1 WHERE b<=>NULL;
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a b
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99 NULL
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INSERT INTO t1 VALUES (1,3);
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ERROR 23000: Duplicate entry '3' for key 'b'
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DROP TABLE t1;
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CREATE TABLE t1 (
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a int default NULL,
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key a (a)
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) ENGINE=HEAP;
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INSERT INTO t1 VALUES (10), (10), (10);
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EXPLAIN SELECT * FROM t1 WHERE a=10;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref a a 5 const 3
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SELECT * FROM t1 WHERE a=10;
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a
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10
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10
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10
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DROP TABLE t1;
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CREATE TABLE t1 (a int not null, primary key(a)) engine=heap;
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INSERT into t1 values (1),(2),(3),(4),(5),(6),(7),(8),(9),(10),(11);
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DELETE from t1 where a < 100;
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SELECT * from t1;
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a
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DROP TABLE t1;
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CREATE TABLE `job_titles` (
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`job_title_id` int(6) unsigned NOT NULL default '0',
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`job_title` char(18) NOT NULL default '',
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PRIMARY KEY (`job_title_id`),
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UNIQUE KEY `job_title_id` (`job_title_id`,`job_title`)
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) ENGINE=HEAP;
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SELECT MAX(job_title_id) FROM job_titles;
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MAX(job_title_id)
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NULL
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DROP TABLE job_titles;
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CREATE TABLE t1 (a INT NOT NULL, B INT, KEY(B)) ENGINE=HEAP;
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INSERT INTO t1 VALUES(1,1), (1,NULL);
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SELECT * FROM t1 WHERE B is not null;
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a B
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1 1
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DROP TABLE t1;
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CREATE TABLE t1 (pseudo char(35) PRIMARY KEY, date int(10) unsigned NOT NULL) ENGINE=HEAP;
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INSERT INTO t1 VALUES ('massecot',1101106491),('altec',1101106492),('stitch+',1101106304),('Seb Corgan',1101106305),('beerfilou',1101106263),('flaker',1101106529),('joce8',5),('M4vrick',1101106418),('gabay008',1101106525),('Vamp irX',1101106291),('ZoomZip',1101106546),('rip666',1101106502),('CBP ',1101106397),('guezpard',1101106496);
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DELETE FROM t1 WHERE date<1101106546;
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SELECT * FROM t1;
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pseudo date
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ZoomZip 1101106546
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DROP TABLE t1;
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create table t1(a char(2)) engine=memory;
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insert into t1 values (NULL), (NULL);
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delete from t1 where a is null;
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insert into t1 values ('2'), ('3');
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select * from t1;
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a
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3
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2
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drop table t1;
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set storage_engine=HEAP;
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create table t1 (v varchar(10), c char(10), t varchar(50));
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insert into t1 values('+ ', '+ ', '+ ');
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set @a=repeat(' ',20);
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insert into t1 values (concat('+',@a),concat('+',@a),concat('+',@a));
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Warnings:
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Note 1265 Data truncated for column 'v' at row 1
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select concat('*',v,'*',c,'*',t,'*') from t1;
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concat('*',v,'*',c,'*',t,'*')
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*+ *+*+ *
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*+ *+*+ *
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`v` varchar(10) DEFAULT NULL,
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`c` char(10) DEFAULT NULL,
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`t` varchar(50) DEFAULT NULL
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) ENGINE=MEMORY DEFAULT CHARSET=latin1
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create table t2 like t1;
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show create table t2;
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Table Create Table
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t2 CREATE TABLE `t2` (
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`v` varchar(10) DEFAULT NULL,
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`c` char(10) DEFAULT NULL,
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`t` varchar(50) DEFAULT NULL
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) ENGINE=MEMORY DEFAULT CHARSET=latin1
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create table t3 select * from t1;
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show create table t3;
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Table Create Table
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t3 CREATE TABLE `t3` (
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`v` varchar(10) DEFAULT NULL,
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`c` char(10) DEFAULT NULL,
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`t` varchar(50) DEFAULT NULL
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) ENGINE=MEMORY DEFAULT CHARSET=latin1
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alter table t1 modify c varchar(10);
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`v` varchar(10) DEFAULT NULL,
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`c` varchar(10) DEFAULT NULL,
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`t` varchar(50) DEFAULT NULL
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) ENGINE=MEMORY DEFAULT CHARSET=latin1
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alter table t1 modify v char(10);
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`v` char(10) DEFAULT NULL,
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`c` varchar(10) DEFAULT NULL,
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`t` varchar(50) DEFAULT NULL
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) ENGINE=MEMORY DEFAULT CHARSET=latin1
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alter table t1 modify t varchar(10);
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Warnings:
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Warning 1265 Data truncated for column 't' at row 2
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`v` char(10) DEFAULT NULL,
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`c` varchar(10) DEFAULT NULL,
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`t` varchar(10) DEFAULT NULL
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) ENGINE=MEMORY DEFAULT CHARSET=latin1
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select concat('*',v,'*',c,'*',t,'*') from t1;
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concat('*',v,'*',c,'*',t,'*')
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*+*+*+ *
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*+*+*+ *
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drop table t1,t2,t3;
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create table t1 (v varchar(10), c char(10), t varchar(50), key(v), key(c), key(t(10)));
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`v` varchar(10) DEFAULT NULL,
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`c` char(10) DEFAULT NULL,
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`t` varchar(50) DEFAULT NULL,
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KEY `v` (`v`),
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KEY `c` (`c`),
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KEY `t` (`t`(10))
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) ENGINE=MEMORY DEFAULT CHARSET=latin1
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select count(*) from t1;
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count(*)
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270
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insert into t1 values(concat('a',char(1)),concat('a',char(1)),concat('a',char(1)));
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select count(*) from t1 where v='a';
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count(*)
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10
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select count(*) from t1 where c='a';
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count(*)
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10
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select count(*) from t1 where t='a';
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count(*)
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10
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select count(*) from t1 where v='a ';
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count(*)
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10
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select count(*) from t1 where c='a ';
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count(*)
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10
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select count(*) from t1 where t='a ';
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count(*)
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10
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select count(*) from t1 where v between 'a' and 'a ';
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count(*)
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10
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select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n';
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count(*)
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10
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select count(*) from t1 where v like 'a%';
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count(*)
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11
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select count(*) from t1 where c like 'a%';
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count(*)
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11
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select count(*) from t1 where t like 'a%';
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count(*)
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11
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select count(*) from t1 where v like 'a %';
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count(*)
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9
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explain select count(*) from t1 where v='a ';
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref v v 13 const 10 Using where
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explain select count(*) from t1 where c='a ';
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref c c 11 const 10 Using where
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explain select count(*) from t1 where t='a ';
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref t t 13 const 10 Using where
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explain select count(*) from t1 where v like 'a%';
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL v NULL NULL NULL 271 Using where
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explain select count(*) from t1 where v between 'a' and 'a ';
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref v v 13 const 10 Using where
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explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n';
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref v v 13 const 10 Using where
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alter table t1 add unique(v);
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ERROR 23000: Duplicate entry '{ ' for key 'v_2'
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select concat('*',v,'*',c,'*',t,'*') as qq from t1 where v='a' order by length(concat('*',v,'*',c,'*',t,'*'));
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qq
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*a*a*a*
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*a *a*a *
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*a *a*a *
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||
*a *a*a *
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||
*a *a*a *
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||
*a *a*a *
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||
*a *a*a *
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*a *a*a *
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*a *a*a *
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*a *a*a *
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explain select * from t1 where v='a';
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref v v 13 const 10 Using where
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select v,count(*) from t1 group by v limit 10;
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v count(*)
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a 1
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a 10
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b 10
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c 10
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d 10
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e 10
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f 10
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g 10
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h 10
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i 10
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select v,count(t) from t1 group by v limit 10;
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v count(t)
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a 1
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a 10
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b 10
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c 10
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d 10
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e 10
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f 10
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g 10
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h 10
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i 10
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select v,count(c) from t1 group by v limit 10;
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v count(c)
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a 1
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a 10
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b 10
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c 10
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d 10
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e 10
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f 10
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g 10
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h 10
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||
i 10
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select sql_big_result trim(v),count(t) from t1 group by v limit 10;
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trim(v) count(t)
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a 1
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a 10
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b 10
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c 10
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d 10
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e 10
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f 10
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g 10
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h 10
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i 10
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select sql_big_result trim(v),count(c) from t1 group by v limit 10;
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trim(v) count(c)
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a 1
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a 10
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b 10
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c 10
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d 10
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e 10
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f 10
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g 10
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h 10
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i 10
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select c,count(*) from t1 group by c limit 10;
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c count(*)
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a 1
|
||
a 10
|
||
b 10
|
||
c 10
|
||
d 10
|
||
e 10
|
||
f 10
|
||
g 10
|
||
h 10
|
||
i 10
|
||
select c,count(t) from t1 group by c limit 10;
|
||
c count(t)
|
||
a 1
|
||
a 10
|
||
b 10
|
||
c 10
|
||
d 10
|
||
e 10
|
||
f 10
|
||
g 10
|
||
h 10
|
||
i 10
|
||
select sql_big_result c,count(t) from t1 group by c limit 10;
|
||
c count(t)
|
||
a 1
|
||
a 10
|
||
b 10
|
||
c 10
|
||
d 10
|
||
e 10
|
||
f 10
|
||
g 10
|
||
h 10
|
||
i 10
|
||
select t,count(*) from t1 group by t limit 10;
|
||
t count(*)
|
||
a 1
|
||
a 10
|
||
b 10
|
||
c 10
|
||
d 10
|
||
e 10
|
||
f 10
|
||
g 10
|
||
h 10
|
||
i 10
|
||
select t,count(t) from t1 group by t limit 10;
|
||
t count(t)
|
||
a 1
|
||
a 10
|
||
b 10
|
||
c 10
|
||
d 10
|
||
e 10
|
||
f 10
|
||
g 10
|
||
h 10
|
||
i 10
|
||
select sql_big_result trim(t),count(t) from t1 group by t limit 10;
|
||
trim(t) count(t)
|
||
a 1
|
||
a 10
|
||
b 10
|
||
c 10
|
||
d 10
|
||
e 10
|
||
f 10
|
||
g 10
|
||
h 10
|
||
i 10
|
||
drop table t1;
|
||
create table t1 (a char(10), unique (a));
|
||
insert into t1 values ('a');
|
||
insert into t1 values ('a ');
|
||
ERROR 23000: Duplicate entry 'a' for key 'a'
|
||
alter table t1 modify a varchar(10);
|
||
insert into t1 values ('a '),('a '),('a '),('a ');
|
||
ERROR 23000: Duplicate entry 'a ' for key 'a'
|
||
insert into t1 values ('a ');
|
||
ERROR 23000: Duplicate entry 'a ' for key 'a'
|
||
insert into t1 values ('a ');
|
||
ERROR 23000: Duplicate entry 'a ' for key 'a'
|
||
insert into t1 values ('a ');
|
||
ERROR 23000: Duplicate entry 'a ' for key 'a'
|
||
update t1 set a='a ' where a like 'a ';
|
||
update t1 set a='a ' where a like 'a ';
|
||
drop table t1;
|
||
create table t1 (v varchar(10), c char(10), t varchar(50), key using btree (v), key using btree (c), key using btree (t(10)));
|
||
show create table t1;
|
||
Table Create Table
|
||
t1 CREATE TABLE `t1` (
|
||
`v` varchar(10) DEFAULT NULL,
|
||
`c` char(10) DEFAULT NULL,
|
||
`t` varchar(50) DEFAULT NULL,
|
||
KEY `v` (`v`) USING BTREE,
|
||
KEY `c` (`c`) USING BTREE,
|
||
KEY `t` (`t`(10)) USING BTREE
|
||
) ENGINE=MEMORY DEFAULT CHARSET=latin1
|
||
select count(*) from t1;
|
||
count(*)
|
||
270
|
||
insert into t1 values(concat('a',char(1)),concat('a',char(1)),concat('a',char(1)));
|
||
select count(*) from t1 where v='a';
|
||
count(*)
|
||
10
|
||
select count(*) from t1 where c='a';
|
||
count(*)
|
||
10
|
||
select count(*) from t1 where t='a';
|
||
count(*)
|
||
10
|
||
select count(*) from t1 where v='a ';
|
||
count(*)
|
||
10
|
||
select count(*) from t1 where c='a ';
|
||
count(*)
|
||
10
|
||
select count(*) from t1 where t='a ';
|
||
count(*)
|
||
10
|
||
select count(*) from t1 where v between 'a' and 'a ';
|
||
count(*)
|
||
10
|
||
select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n';
|
||
count(*)
|
||
10
|
||
explain select count(*) from t1 where v='a ';
|
||
id select_type table type possible_keys key key_len ref rows Extra
|
||
1 SIMPLE t1 ref v v 13 const # Using where
|
||
explain select count(*) from t1 where c='a ';
|
||
id select_type table type possible_keys key key_len ref rows Extra
|
||
1 SIMPLE t1 ref c c 11 const # Using where
|
||
explain select count(*) from t1 where t='a ';
|
||
id select_type table type possible_keys key key_len ref rows Extra
|
||
1 SIMPLE t1 ref t t 13 const # Using where
|
||
explain select count(*) from t1 where v like 'a%';
|
||
id select_type table type possible_keys key key_len ref rows Extra
|
||
1 SIMPLE t1 range v v 13 NULL # Using where
|
||
explain select count(*) from t1 where v between 'a' and 'a ';
|
||
id select_type table type possible_keys key key_len ref rows Extra
|
||
1 SIMPLE t1 ref v v 13 const # Using where
|
||
explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n';
|
||
id select_type table type possible_keys key key_len ref rows Extra
|
||
1 SIMPLE t1 ref v v 13 const # Using where
|
||
alter table t1 add unique(v);
|
||
ERROR 23000: Duplicate entry '{ ' for key 'v_2'
|
||
select concat('*',v,'*',c,'*',t,'*') as qq from t1 where v='a' order by length(concat('*',v,'*',c,'*',t,'*'));
|
||
qq
|
||
*a*a*a*
|
||
*a *a*a *
|
||
*a *a*a *
|
||
*a *a*a *
|
||
*a *a*a *
|
||
*a *a*a *
|
||
*a *a*a *
|
||
*a *a*a *
|
||
*a *a*a *
|
||
*a *a*a *
|
||
explain select * from t1 where v='a';
|
||
id select_type table type possible_keys key key_len ref rows Extra
|
||
1 SIMPLE t1 ref v v 13 const # Using where
|
||
drop table t1;
|
||
create table t1 (a char(10), unique using btree (a)) engine=heap;
|
||
insert into t1 values ('a');
|
||
insert into t1 values ('a ');
|
||
ERROR 23000: Duplicate entry 'a' for key 'a'
|
||
alter table t1 modify a varchar(10);
|
||
insert into t1 values ('a '),('a '),('a '),('a ');
|
||
ERROR 23000: Duplicate entry 'a ' for key 'a'
|
||
insert into t1 values ('a ');
|
||
ERROR 23000: Duplicate entry 'a ' for key 'a'
|
||
insert into t1 values ('a ');
|
||
ERROR 23000: Duplicate entry 'a ' for key 'a'
|
||
insert into t1 values ('a ');
|
||
ERROR 23000: Duplicate entry 'a ' for key 'a'
|
||
update t1 set a='a ' where a like 'a ';
|
||
update t1 set a='a ' where a like 'a ';
|
||
drop table t1;
|
||
create table t1 (v varchar(10), c char(10), t varchar(50), key(v(5)), key(c(5)), key(t(5)));
|
||
show create table t1;
|
||
Table Create Table
|
||
t1 CREATE TABLE `t1` (
|
||
`v` varchar(10) DEFAULT NULL,
|
||
`c` char(10) DEFAULT NULL,
|
||
`t` varchar(50) DEFAULT NULL,
|
||
KEY `v` (`v`(5)),
|
||
KEY `c` (`c`(5)),
|
||
KEY `t` (`t`(5))
|
||
) ENGINE=MEMORY DEFAULT CHARSET=latin1
|
||
drop table t1;
|
||
create table t1 (v varchar(65530), key(v(10)));
|
||
show create table t1;
|
||
Table Create Table
|
||
t1 CREATE TABLE `t1` (
|
||
`v` varchar(65530) DEFAULT NULL,
|
||
KEY `v` (`v`(10))
|
||
) ENGINE=MEMORY DEFAULT CHARSET=latin1
|
||
insert into t1 values(repeat('a',65530));
|
||
select length(v) from t1 where v=repeat('a',65530);
|
||
length(v)
|
||
65530
|
||
drop table t1;
|
||
set storage_engine=MyISAM;
|
||
create table t1 (a bigint unsigned auto_increment primary key, b int,
|
||
key (b, a)) engine=heap;
|
||
insert t1 (b) values (1),(1),(1),(1),(1),(1),(1),(1);
|
||
select * from t1;
|
||
a b
|
||
1 1
|
||
2 1
|
||
3 1
|
||
4 1
|
||
5 1
|
||
6 1
|
||
7 1
|
||
8 1
|
||
drop table t1;
|
||
create table t1 (a int not null, b int not null auto_increment,
|
||
primary key(a, b), key(b)) engine=heap;
|
||
insert t1 (a) values (1),(1),(1),(1),(1),(1),(1),(1);
|
||
select * from t1;
|
||
a b
|
||
1 1
|
||
1 2
|
||
1 3
|
||
1 4
|
||
1 5
|
||
1 6
|
||
1 7
|
||
1 8
|
||
drop table t1;
|
||
create table t1 (a int not null, b int not null auto_increment,
|
||
primary key(a, b)) engine=heap;
|
||
ERROR 42000: Incorrect table definition; there can be only one auto column and it must be defined as a key
|
||
create table t1 (c char(255), primary key(c(90)));
|
||
insert into t1 values ("abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz");
|
||
insert into t1 values ("abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz");
|
||
ERROR 23000: Duplicate entry 'abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijkl' for key 'PRIMARY'
|
||
drop table t1;
|
||
CREATE TABLE t1 (a int, key(a)) engine=heap;
|
||
insert into t1 values (0);
|
||
delete from t1;
|
||
select * from t1;
|
||
a
|
||
insert into t1 values (0), (1);
|
||
select * from t1 where a = 0;
|
||
a
|
||
0
|
||
drop table t1;
|
||
create table t1 (c char(10)) engine=memory;
|
||
create table t2 (c varchar(10)) engine=memory;
|
||
show table status like 't_';
|
||
Name Engine Version Row_format Rows Avg_row_length Data_length Max_data_length Index_length Data_free Auto_increment Create_time Update_time Check_time Collation Checksum Create_options Comment
|
||
t1 MEMORY 10 Fixed 0 11 0 # 0 0 NULL NULL NULL NULL latin1_swedish_ci NULL
|
||
t2 MEMORY 10 Fixed 0 12 0 # 0 0 NULL NULL NULL NULL latin1_swedish_ci NULL
|
||
drop table t1, t2;
|
||
CREATE TABLE t1(a VARCHAR(1), b VARCHAR(2), c VARCHAR(256),
|
||
KEY(a), KEY(b), KEY(c)) ENGINE=MEMORY;
|
||
INSERT INTO t1 VALUES('a','aa',REPEAT('a', 256)),('a','aa',REPEAT('a',256));
|
||
SELECT COUNT(*) FROM t1 WHERE a='a';
|
||
COUNT(*)
|
||
2
|
||
SELECT COUNT(*) FROM t1 WHERE b='aa';
|
||
COUNT(*)
|
||
2
|
||
SELECT COUNT(*) FROM t1 WHERE c=REPEAT('a',256);
|
||
COUNT(*)
|
||
2
|
||
DROP TABLE t1;
|
||
CREATE TABLE t1(c1 VARCHAR(100), c2 INT) ENGINE=MEMORY;
|
||
INSERT INTO t1 VALUES('', 0);
|
||
ALTER TABLE t1 MODIFY c1 VARCHAR(101);
|
||
SELECT c2 FROM t1;
|
||
c2
|
||
0
|
||
DROP TABLE t1;
|