mirror of
https://github.com/MariaDB/server.git
synced 2025-01-18 21:12:26 +01:00
205 lines
5.1 KiB
Text
205 lines
5.1 KiB
Text
drop table if exists t1;
|
|
create table t1 (a int not null,b int not null, primary key (a)) type=heap comment="testing heaps" avg_row_length=100 min_rows=1 max_rows=100;
|
|
insert into t1 values(1,1),(2,2),(3,3),(4,4);
|
|
delete from t1 where a=1 or a=0;
|
|
show keys from t1;
|
|
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment
|
|
t1 0 PRIMARY 1 a NULL NULL NULL NULL HASH
|
|
select * from t1;
|
|
a b
|
|
2 2
|
|
3 3
|
|
4 4
|
|
select * from t1 where a=4;
|
|
a b
|
|
4 4
|
|
update t1 set b=5 where a=4;
|
|
update t1 set b=b+1 where a>=3;
|
|
replace t1 values (3,3);
|
|
select * from t1;
|
|
a b
|
|
2 2
|
|
3 3
|
|
4 6
|
|
alter table t1 add c int not null, add key (c,a);
|
|
drop table t1;
|
|
create table t1 (a int not null,b int not null, primary key (a)) type=heap comment="testing heaps";
|
|
insert into t1 values(1,1),(2,2),(3,3),(4,4);
|
|
delete from t1 where a > 0;
|
|
select * from t1;
|
|
a b
|
|
drop table t1;
|
|
create table t1 (a int not null,b int not null, primary key (a)) type=heap comment="testing heaps";
|
|
insert into t1 values(1,1),(2,2),(3,3),(4,4);
|
|
alter table t1 modify a int not null auto_increment, type=myisam, comment="new myisam table";
|
|
select * from t1;
|
|
a b
|
|
1 1
|
|
2 2
|
|
3 3
|
|
4 4
|
|
drop table t1;
|
|
create table t1 (a int not null) type=heap;
|
|
insert into t1 values (869751),(736494),(226312),(802616);
|
|
select * from t1 where a > 736494;
|
|
a
|
|
869751
|
|
802616
|
|
alter table t1 add unique uniq_id(a);
|
|
select * from t1 where a > 736494;
|
|
a
|
|
869751
|
|
802616
|
|
select * from t1 where a = 736494;
|
|
a
|
|
736494
|
|
select * from t1 where a=869751 or a=736494;
|
|
a
|
|
736494
|
|
869751
|
|
select * from t1 where a in (869751,736494,226312,802616);
|
|
a
|
|
226312
|
|
736494
|
|
802616
|
|
869751
|
|
alter table t1 type=myisam;
|
|
explain select * from t1 where a in (869751,736494,226312,802616);
|
|
table type possible_keys key key_len ref rows Extra
|
|
t1 range uniq_id uniq_id 4 NULL 4 where used; Using index
|
|
drop table t1;
|
|
create table t1 (x int not null, y int not null, key x(x), unique y(y))
|
|
type=heap;
|
|
insert into t1 values (1,1),(2,2),(1,3),(2,4),(2,5),(2,6);
|
|
select * from t1 where x=1;
|
|
x y
|
|
1 3
|
|
1 1
|
|
select * from t1,t1 as t2 where t1.x=t2.y;
|
|
x y x y
|
|
1 1 1 1
|
|
2 2 2 2
|
|
1 3 1 1
|
|
2 4 2 2
|
|
2 5 2 2
|
|
2 6 2 2
|
|
explain select * from t1,t1 as t2 where t1.x=t2.y;
|
|
table type possible_keys key key_len ref rows Extra
|
|
t1 ALL x NULL NULL NULL 6
|
|
t2 eq_ref y y 4 t1.x 1
|
|
drop table t1;
|
|
create table t1 (a int) type=heap;
|
|
insert into t1 values(1);
|
|
select max(a) from t1;
|
|
max(a)
|
|
1
|
|
drop table t1;
|
|
CREATE TABLE t1 ( a int not null default 0, b int not null default 0, key(a), key(b) ) TYPE=HEAP;
|
|
insert into t1 values(1,1),(1,2),(2,3),(1,3),(1,4),(1,5),(1,6);
|
|
select * from t1 where a=1;
|
|
a b
|
|
1 6
|
|
1 5
|
|
1 4
|
|
1 3
|
|
1 2
|
|
1 1
|
|
insert into t1 values(1,1),(1,2),(2,3),(1,3),(1,4),(1,5),(1,6);
|
|
select * from t1 where a=1;
|
|
a b
|
|
1 6
|
|
1 5
|
|
1 4
|
|
1 3
|
|
1 2
|
|
1 1
|
|
1 6
|
|
1 5
|
|
1 4
|
|
1 3
|
|
1 2
|
|
1 1
|
|
drop table t1;
|
|
create table t1 (id int unsigned not null, primary key (id)) type=HEAP;
|
|
insert into t1 values(1);
|
|
select max(id) from t1;
|
|
max(id)
|
|
1
|
|
insert into t1 values(2);
|
|
select max(id) from t1;
|
|
max(id)
|
|
2
|
|
replace into t1 values(1);
|
|
drop table t1;
|
|
create table t1 (n int) type=heap;
|
|
drop table t1;
|
|
create table t1 (n int) type=heap;
|
|
drop table if exists t1;
|
|
CREATE table t1(f1 int not null,f2 char(20) not
|
|
null,index(f2)) type=heap;
|
|
INSERT into t1 set f1=12,f2="bill";
|
|
INSERT into t1 set f1=13,f2="bill";
|
|
INSERT into t1 set f1=14,f2="bill";
|
|
INSERT into t1 set f1=15,f2="bill";
|
|
INSERT into t1 set f1=16,f2="ted";
|
|
INSERT into t1 set f1=12,f2="ted";
|
|
INSERT into t1 set f1=12,f2="ted";
|
|
INSERT into t1 set f1=12,f2="ted";
|
|
INSERT into t1 set f1=12,f2="ted";
|
|
delete from t1 where f2="bill";
|
|
select * from t1;
|
|
f1 f2
|
|
16 ted
|
|
12 ted
|
|
12 ted
|
|
12 ted
|
|
12 ted
|
|
drop table t1;
|
|
create table t1 (btn char(10) not null, key(btn)) type=heap;
|
|
insert into t1 values ("hello"),("hello"),("hello"),("hello"),("hello"),("a"),("b"),("c"),("d"),("e"),("f"),("g"),("h"),("i");
|
|
explain select * from t1 where btn like "q%";
|
|
table type possible_keys key key_len ref rows Extra
|
|
t1 ALL btn NULL NULL NULL 14 where used
|
|
select * from t1 where btn like "q%";
|
|
btn
|
|
alter table t1 add column new_col char(1) not null, add key (btn,new_col), drop key btn;
|
|
update t1 set new_col=btn;
|
|
explain select * from t1 where btn="a";
|
|
table type possible_keys key key_len ref rows Extra
|
|
t1 ALL btn NULL NULL NULL 14 where used
|
|
explain select * from t1 where btn="a" and new_col="a";
|
|
table type possible_keys key key_len ref rows Extra
|
|
t1 ref btn btn 11 const,const 10 where used
|
|
drop table t1;
|
|
CREATE TABLE t1 (
|
|
a int default NULL,
|
|
b int default NULL,
|
|
KEY a (a),
|
|
UNIQUE b (b)
|
|
) type=heap;
|
|
INSERT INTO t1 VALUES (NULL,99),(99,NULL),(1,1),(2,2),(1,3);
|
|
SELECT * FROM t1 WHERE a=NULL;
|
|
a b
|
|
explain SELECT * FROM t1 WHERE a IS NULL;
|
|
table type possible_keys key key_len ref rows Extra
|
|
t1 ref a a 5 const 10 where used
|
|
SELECT * FROM t1 WHERE a<=>NULL;
|
|
a b
|
|
NULL 99
|
|
SELECT * FROM t1 WHERE b=NULL;
|
|
a b
|
|
explain SELECT * FROM t1 WHERE b IS NULL;
|
|
table type possible_keys key key_len ref rows Extra
|
|
t1 ref b b 5 const 1 where used
|
|
SELECT * FROM t1 WHERE b<=>NULL;
|
|
a b
|
|
99 NULL
|
|
INSERT INTO t1 VALUES (1,3);
|
|
Duplicate entry '3' for key 1
|
|
DROP TABLE t1;
|
|
CREATE TABLE t1 (a int not null, primary key(a)) type=heap;
|
|
INSERT into t1 values (1),(2),(3),(4),(5),(6),(7),(8),(9),(10),(11);
|
|
DELETE from t1 where a < 100;
|
|
SELECT * from t1;
|
|
a
|
|
DROP TABLE t1;
|