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b017caefbd
The problem was due to a prior fix for BUG 9676, which limited the rows stored in a temporary table to the LIMIT clause. This optimization is not applicable to non-group queries with aggregate functions. The fix disables the optimization in this case. mysql-test/r/limit.result: Test case for BUG#21787 mysql-test/t/limit.test: Test case for BUG#21787 sql/sql_select.cc: If there is an aggregate function in a non-group query, materialize all rows in the temporary table no matter if there is a LIMIT clause. This is necessary, since the aggregate functions must be computed over all result rows, not just the first LIMIT rows.
92 lines
1.9 KiB
Text
92 lines
1.9 KiB
Text
drop table if exists t1;
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create table t1 (a int primary key, b int not null);
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insert into t1 () values ();
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insert into t1 values (1,1),(2,1),(3,1);
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update t1 set a=4 where b=1 limit 1;
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select * from t1;
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a b
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0 0
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4 1
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2 1
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3 1
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update t1 set b=2 where b=1 limit 2;
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select * from t1;
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a b
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0 0
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4 2
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2 2
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3 1
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update t1 set b=4 where b=1;
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select * from t1;
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a b
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0 0
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4 2
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2 2
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3 4
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delete from t1 where b=2 limit 1;
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select * from t1;
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a b
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0 0
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2 2
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3 4
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delete from t1 limit 1;
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select * from t1;
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a b
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2 2
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3 4
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drop table t1;
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create table t1 (i int);
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insert into t1 (i) values(1),(1),(1);
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delete from t1 limit 1;
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update t1 set i=2 limit 1;
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delete from t1 limit 0;
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update t1 set i=3 limit 0;
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select * from t1;
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i
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2
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1
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drop table t1;
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select 0 limit 0;
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0
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CREATE TABLE t1(id int auto_increment primary key, id2 int, index(id2));
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INSERT INTO t1 (id2) values (0),(0),(0);
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DELETE FROM t1 WHERE id=1;
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INSERT INTO t1 SET id2=0;
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SELECT * FROM t1;
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id id2
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4 0
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2 0
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3 0
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DELETE FROM t1 WHERE id2 = 0 ORDER BY id LIMIT 1;
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SELECT * FROM t1;
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id id2
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4 0
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3 0
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DELETE FROM t1 WHERE id2 = 0 ORDER BY id desc LIMIT 1;
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SELECT * FROM t1;
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id id2
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3 0
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DROP TABLE t1;
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create table t1 (a integer);
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insert into t1 values (1);
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select 1 as a from t1 union all select 1 from dual limit 1;
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a
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1
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(select 1 as a from t1) union all (select 1 from dual) limit 1;
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a
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1
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drop table t1;
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create table t1 (a int);
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insert into t1 values (1),(2),(3),(4),(5),(6),(7);
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explain select count(*) c FROM t1 WHERE a > 0 ORDER BY c LIMIT 3;
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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 7 Using where; Using temporary
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select count(*) c FROM t1 WHERE a > 0 ORDER BY c LIMIT 3;
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c
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7
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explain select sum(a) c FROM t1 WHERE a > 0 ORDER BY c LIMIT 3;
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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 7 Using where; Using temporary
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select sum(a) c FROM t1 WHERE a > 0 ORDER BY c LIMIT 3;
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c
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28
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