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If an outer query is broken, a subquery might not even get set up. EXPLAIN EXTENDED did not expect this and merrily tried to de-ref all of the half-setup info. We now catch this case and print as much as we have, as it doesn't cost us anything (doesn't make regular execution slower). mysql-test/r/explain.result: Show that EXPLAIN EXTENDED with subquery and illegal out query doesn't crash. Show also that SHOW WARNINGS will render an additional Note in the hope of being, well, helpful. mysql-test/t/explain.test: If we have only half a query for EXPLAIN EXTENDED to print (i.e., incomplete subquery info as outer query is illegal), we should provide the user with as much info as we easily can if they ask for it. What we should not do is crash when they come asking for help, that violates etiquette in some countries. sql/item_subselect.cc: If the sub-query's actually set up, print it. Otherwise, elide.
213 lines
9.8 KiB
Text
213 lines
9.8 KiB
Text
drop table if exists t1;
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create table t1 (id int not null, str char(10), unique(str));
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explain select * from t1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 system NULL NULL NULL NULL 0 const row not found
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insert into t1 values (1, null),(2, null),(3, "foo"),(4, "bar");
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select * from t1 where str is null;
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id str
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1 NULL
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2 NULL
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select * from t1 where str="foo";
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id str
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3 foo
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explain select * from t1 where str 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 str str 11 const 1 Using where
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explain select * from t1 where str="foo";
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 const str str 11 const 1
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explain select * from t1 ignore key (str) where str="foo";
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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 NULL NULL NULL NULL 4 Using where
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explain select * from t1 use key (str,str) where str="foo";
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 const str str 11 const 1
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explain select * from t1 use key (str,str,foo) where str="foo";
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ERROR 42000: Key 'foo' doesn't exist in table 't1'
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explain select * from t1 ignore key (str,str,foo) where str="foo";
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ERROR 42000: Key 'foo' doesn't exist in table 't1'
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drop table t1;
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explain select 1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL No tables used
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create table t1 (a int not null);
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explain select count(*) from t1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
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insert into t1 values(1);
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explain select count(*) from t1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
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insert into t1 values(1);
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explain select count(*) from t1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
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drop table t1;
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set names koi8r;
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create table <20><><EFBFBD> (<28><><EFBFBD>0 int, <20><><EFBFBD>1 int, key <20><><EFBFBD>0 (<28><><EFBFBD>0), key <20><><EFBFBD>01 (<28><><EFBFBD>0,<2C><><EFBFBD>1));
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insert into <20><><EFBFBD> (<28><><EFBFBD>0) values (1);
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insert into <20><><EFBFBD> (<28><><EFBFBD>0) values (2);
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explain select <20><><EFBFBD>0 from <20><><EFBFBD> where <20><><EFBFBD>0=1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE <09><><EFBFBD> ref <09><><EFBFBD>0,<2C><><EFBFBD>01 <09><><EFBFBD>0 5 const 1 Using where; Using index
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drop table <20><><EFBFBD>;
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set names latin1;
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select 3 into @v1;
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explain select 3 into @v1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL No tables used
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create table t1(f1 int, f2 int);
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insert into t1 values (1,1);
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create view v1 as select * from t1 where f1=1;
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explain extended select * from v1 where f2=1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 system NULL NULL NULL NULL 1 100.00
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Warnings:
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Note 1003 select '1' AS `f1`,'1' AS `f2` from `test`.`t1` where 1
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explain extended select * from t1 where 0;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
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Warnings:
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Note 1003 select `test`.`t1`.`f1` AS `f1`,`test`.`t1`.`f2` AS `f2` from `test`.`t1` where 0
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explain extended select * from t1 where 1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 system NULL NULL NULL NULL 1 100.00
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Warnings:
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Note 1003 select '1' AS `f1`,'1' AS `f2` from `test`.`t1` where 1
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explain extended select * from t1 having 0;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL Impossible HAVING
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Warnings:
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Note 1003 select `test`.`t1`.`f1` AS `f1`,`test`.`t1`.`f2` AS `f2` from `test`.`t1` having 0
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explain extended select * from t1 having 1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 system NULL NULL NULL NULL 1 100.00
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Warnings:
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Note 1003 select '1' AS `f1`,'1' AS `f2` from `test`.`t1` having 1
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drop view v1;
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drop table t1;
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CREATE TABLE t1(c INT);
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INSERT INTO t1 VALUES (),();
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CREATE TABLE t2 (b INT,
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b));
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INSERT INTO t2 VALUES (),(),();
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EXPLAIN SELECT 1 FROM
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(SELECT 1 FROM t2,t1 WHERE b < c GROUP BY 1 LIMIT 1) AS d2;
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id select_type table type possible_keys key key_len ref rows Extra
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X X X X X X X X X const row not found
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X X X X X X X X X
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X X X X X X X X X Range checked for each record (index map: 0xFFFFFFFFFF)
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DROP TABLE t2;
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DROP TABLE t1;
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CREATE TABLE t1(a INT);
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CREATE TABLE t2(a INT);
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INSERT INTO t1 VALUES (1),(2);
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INSERT INTO t2 VALUES (1),(2);
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EXPLAIN EXTENDED SELECT 1
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FROM (SELECT COUNT(DISTINCT t1.a) FROM t1,t2 GROUP BY t1.a) AS s1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 100.00
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2 DERIVED t1 ALL NULL NULL NULL NULL 2 100.00 Using temporary; Using filesort
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2 DERIVED t2 ALL NULL NULL NULL NULL 2 100.00 Using join buffer
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Warnings:
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Note 1003 select 1 AS `1` from (select count(distinct `test`.`t1`.`a`) AS `COUNT(DISTINCT t1.a)` from `test`.`t1` join `test`.`t2` group by `test`.`t1`.`a`) `s1`
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EXPLAIN EXTENDED SELECT 1
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FROM (SELECT COUNT(DISTINCT t1.a) FROM t1,t2 GROUP BY t1.a) AS s1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 100.00
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2 DERIVED t1 ALL NULL NULL NULL NULL 2 100.00 Using temporary; Using filesort
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2 DERIVED t2 ALL NULL NULL NULL NULL 2 100.00 Using join buffer
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Warnings:
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Note 1003 select 1 AS `1` from (select count(distinct `test`.`t1`.`a`) AS `COUNT(DISTINCT t1.a)` from `test`.`t1` join `test`.`t2` group by `test`.`t1`.`a`) `s1`
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prepare s1 from
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'EXPLAIN EXTENDED SELECT 1
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FROM (SELECT COUNT(DISTINCT t1.a) FROM t1,t2 GROUP BY t1.a) AS s1';
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execute s1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 100.00
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2 DERIVED t1 ALL NULL NULL NULL NULL 2 100.00 Using temporary; Using filesort
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2 DERIVED t2 ALL NULL NULL NULL NULL 2 100.00 Using join buffer
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Warnings:
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Note 1003 select 1 AS `1` from (select count(distinct `test`.`t1`.`a`) AS `COUNT(DISTINCT t1.a)` from `test`.`t1` join `test`.`t2` group by `test`.`t1`.`a`) `s1`
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prepare s1 from
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'EXPLAIN EXTENDED SELECT 1
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FROM (SELECT COUNT(DISTINCT t1.a) FROM t1,t2 GROUP BY t1.a) AS s1';
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execute s1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 100.00
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2 DERIVED t1 ALL NULL NULL NULL NULL 2 100.00 Using temporary; Using filesort
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2 DERIVED t2 ALL NULL NULL NULL NULL 2 100.00 Using join buffer
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Warnings:
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Note 1003 select 1 AS `1` from (select count(distinct `test`.`t1`.`a`) AS `COUNT(DISTINCT t1.a)` from `test`.`t1` join `test`.`t2` group by `test`.`t1`.`a`) `s1`
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execute s1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 100.00
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2 DERIVED t1 ALL NULL NULL NULL NULL 2 100.00 Using temporary; Using filesort
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2 DERIVED t2 ALL NULL NULL NULL NULL 2 100.00 Using join buffer
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Warnings:
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Note 1003 select 1 AS `1` from (select count(distinct `test`.`t1`.`a`) AS `COUNT(DISTINCT t1.a)` from `test`.`t1` join `test`.`t2` group by `test`.`t1`.`a`) `s1`
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DROP TABLE t1,t2;
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CREATE TABLE t1 (a INT PRIMARY KEY);
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EXPLAIN EXTENDED SELECT COUNT(a) FROM t1 USE KEY(a);
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ERROR 42000: Key 'a' doesn't exist in table 't1'
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DROP TABLE t1;
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CREATE TABLE t1(a LONGTEXT);
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INSERT INTO t1 VALUES (repeat('a',@@global.max_allowed_packet));
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INSERT INTO t1 VALUES (repeat('b',@@global.max_allowed_packet));
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EXPLAIN SELECT DISTINCT 1 FROM t1,
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(SELECT DISTINCTROW a AS away FROM t1 GROUP BY a WITH ROLLUP) as d1
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WHERE t1.a = d1.a;
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ERROR 42S22: Unknown column 'd1.a' in 'where clause'
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DROP TABLE t1;
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#
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# Bug#37870: Usage of uninitialized value caused failed assertion.
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#
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create table t1 (dt datetime not null, t time not null);
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create table t2 (dt datetime not null);
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insert into t1 values ('2001-01-01 1:1:1', '1:1:1'),
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('2001-01-01 1:1:1', '1:1:1');
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insert into t2 values ('2001-01-01 1:1:1'), ('2001-01-01 1:1:1');
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flush tables;
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EXPLAIN SELECT OUTR.dt FROM t1 AS OUTR WHERE OUTR.dt IN (SELECT INNR.dt FROM t2 AS INNR WHERE OUTR.dt IS NULL );
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY OUTR ALL NULL NULL NULL NULL 2 Using where
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2 DEPENDENT SUBQUERY INNR ALL NULL NULL NULL NULL 2 Using where
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flush tables;
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SELECT OUTR.dt FROM t1 AS OUTR WHERE OUTR.dt IN (SELECT INNR.dt FROM t2 AS INNR WHERE OUTR.dt IS NULL );
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dt
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flush tables;
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EXPLAIN SELECT OUTR.dt FROM t1 AS OUTR WHERE OUTR.dt IN ( SELECT INNR.dt FROM t2 AS INNR WHERE OUTR.t < '2005-11-13 7:41:31' );
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY OUTR ALL NULL NULL NULL NULL 2 Using where
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2 DEPENDENT SUBQUERY INNR ALL NULL NULL NULL NULL 2 Using where
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flush tables;
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SELECT OUTR.dt FROM t1 AS OUTR WHERE OUTR.dt IN ( SELECT INNR.dt FROM t2 AS INNR WHERE OUTR.t < '2005-11-13 7:41:31' );
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dt
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2001-01-01 01:01:01
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2001-01-01 01:01:01
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drop tables t1, t2;
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#
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# Bug#48295:
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# explain extended crash with subquery and ONLY_FULL_GROUP_BY sql_mode
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#
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CREATE TABLE t1 (f1 INT);
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SELECT @@session.sql_mode INTO @old_sql_mode;
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SET SESSION sql_mode='ONLY_FULL_GROUP_BY';
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EXPLAIN EXTENDED SELECT 1 FROM t1
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WHERE f1 > ALL( SELECT t.f1 FROM t1,t1 AS t );
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ERROR 42000: Mixing of GROUP columns (MIN(),MAX(),COUNT(),...) with no GROUP columns is illegal if there is no GROUP BY clause
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SHOW WARNINGS;
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Level Code Message
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Error 1140 Mixing of GROUP columns (MIN(),MAX(),COUNT(),...) with no GROUP columns is illegal if there is no GROUP BY clause
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Note 1003 select 1 AS `1` from `test`.`t1` where <not>(<exists>(...))
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SET SESSION sql_mode=@old_sql_mode;
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DROP TABLE t1;
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End of 5.1 tests.
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