path: root/mysql-test/main/rownum.result

CREATE OR REPLACE TABLE t1(a int, b int) engine=aria;
CREATE OR REPLACE TABLE t2(a int, b int) engine=aria;
insert into t1 values (1,10),(2,20),(3,30);
insert into t2 values (2,21),(3,31),(4,41);
#
# Simple selects
#
select a,b,rownum() from t1;
a	b	rownum()
1	10	1
2	20	2
3	30	3
select a,b,rownum() from t1 where rownum() < 2;
a	b	rownum()
1	10	1
select a,b from t1 where rownum() <= 2;
a	b
1	10
2	20
select a,b from t1 where rownum() > 2;
a	b
#
# Subqueries
#
select t1.a,rownum(),t3.a,t3.t2_rownum from t1, (select t2.a,rownum() as t2_rownum from t2 where rownum() <=2) t3;
a	rownum()	a	t2_rownum
1	1	2	1
1	2	3	2
2	3	2	1
2	4	3	2
3	5	2	1
3	6	3	2
select t1.a, (select t2.b from t2 where t1.a=t2.a and rownum() <= 1) 'b' from t1;
a	b
1	NULL
2	21
3	31
select t1.a, t3.a from t1, (select * from t2 where rownum() <= 2) t3;
a	a
1	2
1	3
2	2
2	3
3	2
3	3
select * from (select tt.*,rownum() as id from (select * from t1) tt) t3 where id>2;
a	b	id
3	30	3
#
# Joins
#
select t1.a,t1.b,t2.a,t2.b,rownum() from t1,t2 where rownum() <= 4;
a	b	a	b	rownum()
1	10	2	21	1
2	20	2	21	2
3	30	2	21	3
1	10	3	31	4
select *,rownum() from t1,t2 where t1.a=t2.a and rownum()<=2;
a	b	a	b	rownum()
2	20	2	21	1
3	30	3	31	2
select * from t1 left join t2 on (t2.a=t1.a and rownum()=0);
a	b	a	b
1	10	NULL	NULL
2	20	NULL	NULL
3	30	NULL	NULL
select * from t1 left join t2 on (t2.a=t1.a and rownum()>1);
a	b	a	b
1	10	NULL	NULL
2	20	NULL	NULL
3	30	NULL	NULL
select * from t1 left join t2 on (t2.a=t1.a and rownum()<1);
a	b	a	b
1	10	NULL	NULL
2	20	NULL	NULL
3	30	NULL	NULL
select * from t1 left join t2 on (t2.a=t1.a and rownum()=1);
a	b	a	b
2	20	2	21
1	10	NULL	NULL
3	30	NULL	NULL
select * from t1 left join t2 on (t2.a=t1.a and rownum()>=1);
a	b	a	b
2	20	2	21
3	30	3	31
1	10	NULL	NULL
#
# Union
#
select * from t1 where rownum() <=2 union select * from t2 where rownum()<= 1;
a	b
1	10
2	20
2	21
#
# Order by
#
select * from t1 where rownum() <= 2 order by a desc;
a	b
2	20
1	10
explain select * from t1 where rownum() <= 2 order by a desc;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using where; Using filesort
select t1.a,t1.b,rownum() from t1 where rownum() <= 2 order by a desc;
a	b	rownum()
2	20	2
1	10	1
explain select t1.a,t1.b,rownum() from t1 where rownum() <= 2 order by a desc;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using where; Using temporary; Using filesort
select *,rownum() from t1,t2;
a	b	a	b	rownum()
1	10	2	21	1
2	20	2	21	2
3	30	2	21	3
1	10	3	31	4
2	20	3	31	5
3	30	3	31	6
1	10	4	41	7
2	20	4	41	8
3	30	4	41	9
select *,rownum() from t1,t2 order by t2.a desc, t1.a desc;
a	b	a	b	rownum()
3	30	4	41	9
2	20	4	41	8
1	10	4	41	7
3	30	3	31	6
2	20	3	31	5
1	10	3	31	4
3	30	2	21	3
2	20	2	21	2
1	10	2	21	1
select * from (select * from t1 order by a desc) as t where rownum() <= 2;
a	b
3	30
2	20
select * from t1,t2 where t1.a=t2.a and rownum()<=2 order by t1.a,t2.a;
a	b	a	b
2	20	2	21
3	30	3	31
#
# Having
#
select t1.a, sum(t1.b), rownum() as 'r' from t1 group by t1.a having r <= 2;
a	sum(t1.b)	r
1	10	1
2	20	2
select * from t1 having rownum() <= 2;
a	b
1	10
2	20
select t1.a, sum(t1.b), rownum() from t1 group by t1.a;
a	sum(t1.b)	rownum()
1	10	1
2	20	2
3	30	3
select t1.a, sum(t1.b), rownum() as 'r' from t1 group by t1.a having r <= 2;
a	sum(t1.b)	r
1	10	1
2	20	2
select t1.a, sum(t1.b), rownum() as 'r' from t1 group by t1.a having rownum() <= 2;
a	sum(t1.b)	r
1	10	1
2	20	2
select t1.a, sum(t1.b), rownum() as 'r' from t1 group by t1.a having r <= 2 order by a desc;
a	sum(t1.b)	r
2	20	2
1	10	1
select t1.a, sum(t1.b), rownum() as 'r' from t1 group by t1.a having rownum() <= 2 order by a desc;
a	sum(t1.b)	r
2	20	2
1	10	1
#
# Sum functions
#
select max(rownum()),min(rownum()) from t1;
max(rownum())	min(rownum())
3	1
select sum(rownum()),avg(rownum()) from t1;
sum(rownum())	avg(rownum())
6	2.0000
#
# Group by
#
select t1.a,sum(t1.b) from t1 where rownum() < 2 group by t1.a;
a	sum(t1.b)
1	10
select t1.a,sum(t2.b) from t1 JOIN t2 ON (t1.a=t2.a) where rownum() <= 2 group by t1.a;
a	sum(t2.b)
2	21
3	31
select * from (select t1.a,sum(t2.b) from t1 JOIN t2 ON (t1.a=t2.a) group by t1.a) as t where rownum() <= 1;
a	sum(t2.b)
2	21
select t1.a,sum(rownum()),count(*) from t1 where rownum() <= 2 group by t1.a;
a	sum(rownum())	count(*)
1	1	1
2	2	1
select * from (select t1.a,sum(t1.b) from t1 group by t1.a) as t3 where rownum() < 2;
a	sum(t1.b)
1	10
create table t3 (a int) engine=myisam;
insert into t3 values (3),(5),(5),(3);
select a, max(rownum()) from t3 group by a;
a	max(rownum())
3	4
5	3
drop table t3;
CREATE TABLE t3 (
a int(11) DEFAULT NULL,
b varchar(1024) DEFAULT NULL
);
insert into t3 select mod(seq*3,20)+1, repeat(char(33+mod(seq,90)),mod(seq,10)*100) from seq_1_to_23;
SELECT sq.a,length(sq.f) FROM (SELECT a, GROUP_CONCAT(b,b) AS f FROM t3 GROUP BY a ORDER BY a desc) as sq WHERE ROWNUM() <= 10;
a	length(sq.f)
20	600
19	1200
18	1800
17	400
16	1000
15	1600
14	200
13	800
12	1400
11	0
drop table t3;
#
# Prepared statements
#
PREPARE stmt1 from "select a,b,rownum() from t1 where rownum() <= 2";
execute stmt1;
a	b	rownum()
1	10	1
2	20	2
execute stmt1;
a	b	rownum()
1	10	1
2	20	2
deallocate prepare stmt1;
#
# Views
#
create view v1 as select t1.a,rownum() from t1;
select * from v1;
a	rownum()
1	1
2	2
3	3
select t1.a,v1.* from t1,v1 where t1.a=v1.a;
a	a	rownum()
1	1	1
2	2	2
3	3	3
drop view v1;
CREATE TABLE t3 (a INT);
INSERT INTO t3 VALUES (1),(2),(3);
CREATE VIEW v1 AS SELECT a FROM t3 WHERE ROWNUM() <= 2;
SELECT * FROM v1;
a
1
2
drop view v1;
drop table t3;
#
# Reserved words
#
create table t4 (a int, rownum int);
insert into t4 (a,rownum) values (1,2);
select t4.a,t4.rownum from t4;
a	rownum
1	2
drop table t4;
#
# Test Oracle mode
#
set SQL_MODE=ORACLE;
select t1.a,rownum from t1 where rownum<=2;
a	rownum
1	1
2	2
select t1.a,rownum() from t1 where rownum()<=2;
a	rownum()
1	1
2	2
create table t4 (a int, rownum int);
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'rownum int)' at line 1
DECLARE
CURSOR c_cursor
IS select a,b,rownum from t1 where rownum <= 2;
v_a  t1.a%TYPE;
v_b  t1.b%TYPE;
v_rn t1.a%TYPE;
BEGIN
OPEN c_cursor;
FETCH c_cursor INTO v_a, v_b, v_rn;
WHILE c_cursor%FOUND LOOP
SELECT concat(v_a,'--',v_b,'--',v_rn);
FETCH c_cursor INTO v_a, v_b, v_rn;
END LOOP;
CLOSE c_cursor;
END;|
concat(v_a,'--',v_b,'--',v_rn)
1--10--1
concat(v_a,'--',v_b,'--',v_rn)
2--20--2
select a, rownum from t1 group by a, rownum having rownum < 3;
a	rownum
1	1
2	2
select a, rownum as r from t1 group by a, rownum having r < 3;
a	r
1	1
2	2
select a, rownum from t1 group by a, rownum having "rownum" < 3;
a	rownum
1	1
2	2
select a, rownum from t1 group by a, rownum having rownum < 3 order by a desc;
a	rownum
2	2
1	1
select a, rownum as r from t1 group by a, rownum having r < 3 order by a desc;
a	r
2	2
1	1
select a, rownum from t1 group by a, rownum having "rownum" < 3 order by a desc;
a	rownum
2	2
1	1
set SQL_MODE=DEFAULT;
# Cleanup
drop table t1,t2;
#
# INSERT
#
create table t1 (a int not null primary key, b int);
insert into t1 values (1,rownum()),(2,rownum()),(3,rownum());
select * from t1;
a	b
1	1
2	2
3	3
drop table t1;
#
# INSERT DELAYED
#
create table t1 (a int not null primary key, b int);
insert delayed into t1 values (1,rownum()),(2,rownum()),(3,rownum());
select * from t1;
a	b
1	1
2	2
3	3
drop table t1;
#
# INSERT IGNORED
#
create table t1 (a int not null primary key, b int);
insert ignore into t1 values (1,rownum()),(2,rownum()),(2,rownum()),(3,rownum());
Warnings:
Warning	1062	Duplicate entry '2' for key 'PRIMARY'
select * from t1;
a	b
1	1
2	2
3	4
delete from t1;
insert ignore into t1 select * from (values (1,rownum()),(2,rownum()),(2,rownum()),(3,rownum())) t;
Warnings:
Warning	1062	Duplicate entry '2' for key 'PRIMARY'
select * from t1;
a	b
1	1
2	2
3	4
drop table t1;
#
# INSERT ... RETURNING
#
create or replace table t1 (a int);
insert into t1 values (1),(2) returning a, rownum();
a	rownum()
1	1
2	2
drop table t1;
#
# UPDATE
#
create table t1 (a int not null primary key, b int);
insert into t1 values (1,1),(2,2),(3,3);
update t1 set b=0;
update t1 set b=rownum()+1;
select * from t1;
a	b
1	2
2	3
3	4
update t1 set b=0;
update t1 set b=rownum() where a < 10 and rownum() < 2;
select * from t1;
a	b
1	1
2	0
3	0
drop table t1;
create table t1 (a int);
insert into t1 values (10),(20),(30);
update t1 set a = rownum();
select * from t1;
a
1
2
3
update t1 set a = rownum();
select * from t1;
a
1
2
3
drop table t1;
#
# DELETE
#
create table t1 (a int not null primary key, b int);
insert into t1 values (1,1),(2,0),(3,0);
delete from t1 where a < 10 and rownum() < 2;
select * from t1;
a	b
2	0
3	0
drop table t1;
#
# MULTI-TABLE-DELETE
#
create table t1 (a int not null primary key);
insert into t1 values (1),(2),(3);
create table t2 (a int not null primary key);
insert into t2 values (1),(2),(3);
delete t1,t2 from t1,t2 where t1.a=t2.a and rownum() <= 2;
select * from t1;
a
3
select * from t2;
a
3
drop table t1,t2;
#
# MULTI-TABLE-UPDATE
CREATE TABLE t1 (ID INT);
CREATE TABLE t2 (ID INT,
s1 TEXT, s2 TEXT, s3 VARCHAR(10), s4 TEXT, s5 VARCHAR(10));
INSERT INTO t1 VALUES (1),(2);
INSERT INTO t2 VALUES (1,'test', 'test', 'test', 'test', 'test'),
(2,'test', 'test', 'test', 'test', 'test');
SELECT * FROM t1 LEFT JOIN t2 USING(ID);
ID	s1	s2	s3	s4	s5
1	test	test	test	test	test
2	test	test	test	test	test
UPDATE t1 LEFT JOIN t2 USING(ID) SET s1 = 'changed';
select * from t2;
ID	s1	s2	s3	s4	s5
1	changed	test	test	test	test
2	changed	test	test	test	test
update t2 set s1="";
UPDATE t1 LEFT JOIN t2 USING(ID) SET s1 = 'changed' where rownum() <=1;
select * from t2;
ID	s1	s2	s3	s4	s5
1	changed	test	test	test	test
2		test	test	test	test
drop table t1,t2;
#
# LOAD DATA
#
create table t1 (a int, b int, c int);
load data infile '../../std_data/loaddata7.dat' into table t1 fields terminated by ',' lines terminated by "\r\n" (a,b) set c=rownum();
select * from t1;
a	b	c
2	2	1
3	3	2
4	4	3
5	5	4
6	6	5
drop table t1;
#
# LIMIT OPTIMIZATION
#
create table t1 (a int);
insert into t1 select seq from seq_1_to_100;
flush status;
select * from t1 where rownum() <= 3;
a
1
2
3
show status like "Rows_read";
Variable_name	Value
Rows_read	3
flush status;
select * from t1 where rownum() <= 4 and rownum() <= 3;
a
1
2
3
show status like "Rows_read";
Variable_name	Value
Rows_read	3
flush status;
select * from t1 where rownum() < 4 and a > 10;
a
11
12
13
show status like "Rows_read";
Variable_name	Value
Rows_read	13
flush status;
select * from t1 where 3 >= rownum();
a
1
2
3
show status like "Rows_read";
Variable_name	Value
Rows_read	3
flush status;
select * from t1 where 4 > rownum() and a > 20;
a
21
22
23
show status like "Rows_read";
Variable_name	Value
Rows_read	23
flush status;
select * from t1 where rownum() = 1 and a > 10;
a
11
show status like "Rows_read";
Variable_name	Value
Rows_read	11
flush status;
select * from t1 where a > 30 && 1 = rownum();
a
31
show status like "Rows_read";
Variable_name	Value
Rows_read	31
flush status;
# No limit optimization
select * from t1 where rownum() > 10;
a
show status like "Rows_read";
Variable_name	Value
Rows_read	100
flush status;
select * from t1 where 10 < rownum();
a
show status like "Rows_read";
Variable_name	Value
Rows_read	100
flush status;
select * from t1 where rownum() >= 10;
a
show status like "Rows_read";
Variable_name	Value
Rows_read	100
flush status;
select * from t1 where 10 < rownum();
a
show status like "Rows_read";
Variable_name	Value
Rows_read	100
flush status;
select * from t1 where 10 <= rownum();
a
show status like "Rows_read";
Variable_name	Value
Rows_read	100
flush status;
select * from t1 where 2 = rownum();
a
show status like "Rows_read";
Variable_name	Value
Rows_read	100
flush status;
select * from t1 where rownum() = 2;
a
show status like "Rows_read";
Variable_name	Value
Rows_read	100
flush status;
select * from t1 where rownum() <= 0;
a
show status like "Rows_read";
Variable_name	Value
Rows_read	100
flush status;
select *,rownum() from t1 where rownum() < 10 limit 4, 4;
a	rownum()
5	5
6	6
7	7
8	8
show status like "Rows_read";
Variable_name	Value
Rows_read	8
flush status;
select * from t1 where rownum() < 10 order by a;
a
1
2
3
4
5
6
7
8
9
show status like "Rows_read";
Variable_name	Value
Rows_read	100
flush status;
# rownum and limit
select * from t1 where rownum() < 4 limit 10;
a
1
2
3
show status like "Rows_read";
Variable_name	Value
Rows_read	3
flush status;
select * from t1 where rownum() < 10 limit 4;
a
1
2
3
4
show status like "Rows_read";
Variable_name	Value
Rows_read	4
drop table t1;
#
# Rownum examples from Woqutech
#
set SQL_MODE=ORACLE;
create table t1 (c1 int ,c2 varchar(20)) engine=myisam;
insert into t1 values (1, 'aaa'),(2, 'bbb'),(3, 'ccc'),(4, 'ddd'),(5, 'eee');
update t1 set c2 = 'xxx' where rownum = 2;
select * from t1 where c2='xxx';
c1	c2
update t1 set c2 = 'xxx' where  rownum < 3;
select * from t1 where c2='xxx';
c1	c2
1	xxx
2	xxx
delete from t1 where rownum = 2;
select count(*) from t1;
count(*)
5
delete from t1 where rownum < 3;
select count(*) from t1;
count(*)
3
delete from t1 where c1=rownum ;
select count(*) from t1;
count(*)
3
delete from t1 where c1=rownum+2 ;
select count(*) from t1;
count(*)
0
set SQL_MODE=DEFAULT;
drop table t1;
#
# Rownum() used in not supported places (returns 0 or gives an error)
#
set @a=rownum();
select @a;
@a
0
create or replace table t (a int, b int as (rownum()) virtual);
ERROR HY000: Function or expression 'rownum()' cannot be used in the GENERATED ALWAYS AS clause of `b`
create table t1 (a int);
insert into t1 values (3),(1),(5),(8),(4);
handler t1 open;
handler t1 read next where rownum() < 1;
ERROR HY000: Function or expression 'rownum()' cannot be used in the WHERE clause of `HANDLER`
handler t1 close;
drop table t1;
create table t1 (a int not null primary key, b int);
insert into t1 values (1,1),(2,2),(3,3);
create function f() returns int return rownum();
select a, rownum(), f() from t1;
a	rownum()	f()
1	1	0
2	2	0
3	3	0
drop function f;
drop table t1;
create or replace table t1 (a int, r int);
create trigger tr before update on t1 for each row set NEW.r = rownum();
insert into t1 (a) values (1),(2);
select * from t1;
a	r
1	NULL
2	NULL
update t1 set a=a+10;
select * from t1;
a	r
11	0
12	0
drop trigger tr;
drop table t1;
#
# LIMIT optimisation
#
create table t1 (a int);
insert into t1 values (1),(2),(3),(4),(5);
flush status;
select * from (select a from t1 where a < 1000) as tt where rownum() <= 2;
a
1
2
show status like "Rows_read";
Variable_name	Value
Rows_read	2
explain extended select * from (select a from t1 where a < 1000) as tt where rownum() <= 2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
Warnings:
Note	1003	/* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 limit 2) `tt` where rownum() <= 2 limit 2
prepare stmt from "select * from (select a from t1 where a < 1000) as tt where rownum() <= 2";
flush status;
execute stmt;
a
1
2
show status like "Rows_read";
Variable_name	Value
Rows_read	2
flush status;
execute stmt;
a
1
2
show status like "Rows_read";
Variable_name	Value
Rows_read	2
deallocate prepare stmt;
flush status;
select * from (select a from t1 where a < 1000 group by a) as tt where rownum() <= 2;
a
1
2
show status like "Rows_read";
Variable_name	Value
Rows_read	5
explain extended select * from (select a from t1 where a < 1000 group by a) as tt where rownum() <= 2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where; Using temporary; Using filesort
Warnings:
Note	1003	/* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 group by `test`.`t1`.`a` limit 2) `tt` where rownum() <= 2 limit 2
prepare stmt from "select * from (select a from t1 where a < 1000 group by a) as tt where rownum() <= 2";
execute stmt;
a
1
2
execute stmt;
a
1
2
deallocate prepare stmt;
flush status;
select * from (select a from t1 where a < 1000 group by a order by 1) as tt where rownum() <= 2;
a
1
2
show status like "Rows_read";
Variable_name	Value
Rows_read	5
explain extended select * from (select a from t1 where a < 1000 group by a order by 1) as tt where rownum() <= 2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where; Using temporary; Using filesort
Warnings:
Note	1003	/* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 group by `test`.`t1`.`a` order by 1 limit 2) `tt` where rownum() <= 2 limit 2
prepare stmt from "select * from (select a from t1 where a < 1000 group by a order by 1) as tt where rownum() <= 2";
execute stmt;
a
1
2
execute stmt;
a
1
2
deallocate prepare stmt;
flush status;
select * from (select a from t1 where a < 1000 union select 10) as tt where rownum() <= 2;
a
1
2
show status like "Rows_read";
Variable_name	Value
Rows_read	5
explain extended select * from (select a from t1 where a < 1000 union select 10) as tt where rownum() <= 2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
3	UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	NULL	
Warnings:
Note	1003	/* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 union /* select#3 */ select 10 AS `10` limit 2) `tt` where rownum() <= 2 limit 2
prepare stmt from "select * from (select a from t1 where a < 1000 union select 10) as tt where rownum() <= 2";
execute stmt;
a
1
2
execute stmt;
a
1
2
deallocate prepare stmt;
# Other limit
select * from (select a from t1 where a < 1000 group by a order by 1 limit 1) as tt where rownum() <= 2;
a
1
explain extended select * from (select a from t1 where a < 1000 group by a order by 1 limit 1) as tt where rownum() <= 2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where; Using temporary; Using filesort
Warnings:
Note	1003	/* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 group by `test`.`t1`.`a` order by 1 limit 1) `tt` where rownum() <= 2 limit 2
prepare stmt from "select * from (select a from t1 where a < 1000 group by a order by 1 limit 1) as tt where rownum() <= 2";
execute stmt;
a
1
execute stmt;
a
1
deallocate prepare stmt;
# Other limit less
select * from (select a from t1 where a < 1000 group by a order by 1 limit 10) as tt where rownum() <= 2;
a
1
2
explain extended select * from (select a from t1 where a < 1000 group by a order by 1 limit 10) as tt where rownum() <= 2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where; Using temporary; Using filesort
Warnings:
Note	1003	/* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 group by `test`.`t1`.`a` order by 1 limit 2) `tt` where rownum() <= 2 limit 2
prepare stmt from "select * from (select a from t1 where a < 1000 group by a order by 1 limit 10) as tt where rownum() <= 2";
execute stmt;
a
1
2
execute stmt;
a
1
2
deallocate prepare stmt;
select * from (select a from t1 where a < 1000 union select 10 limit 1) as tt where rownum() <= 2;
a
1
explain extended select * from (select a from t1 where a < 1000 union select 10 limit 1) as tt where rownum() <= 2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
3	UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	NULL	
Warnings:
Note	1003	/* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 union /* select#3 */ select 10 AS `10` limit 1) `tt` where rownum() <= 2 limit 2
prepare stmt from "select * from (select a from t1 where a < 1000 union select 10 limit 1) as tt where rownum() <= 2";
execute stmt;
a
1
execute stmt;
a
1
deallocate prepare stmt;
# < rownum
select * from (select a from t1 where a < 1000) as tt where rownum() < 2;
a
1
explain extended select * from (select a from t1 where a < 1000) as tt where rownum() < 2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
Warnings:
Note	1003	/* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 limit 1) `tt` where rownum() < 2 limit 1
prepare stmt from "select * from (select a from t1 where a < 1000) as tt where rownum() < 2";
execute stmt;
a
1
execute stmt;
a
1
deallocate prepare stmt;
# Simple expression
select * from (select a from t1 where a < 1000) as tt where rownum() <= 1+1;
a
1
2
explain extended select * from (select a from t1 where a < 1000) as tt where rownum() <= 1+1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
Warnings:
Note	1003	/* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 limit 2) `tt` where rownum() <= <cache>(1 + 1) limit 2
prepare stmt from "select * from (select a from t1 where a < 1000) as tt where rownum() <= 1+1";
execute stmt;
a
1
2
execute stmt;
a
1
2
deallocate prepare stmt;
# Simple expression reversed
select * from (select a from t1 where a < 1000) as tt where  1+1 >= rownum();
a
1
2
explain extended select * from (select a from t1 where a < 1000) as tt where  1+1 >= rownum();
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
Warnings:
Note	1003	/* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 limit 2) `tt` where <cache>(1 + 1) >= rownum() limit 2
prepare stmt from "select * from (select a from t1 where a < 1000) as tt where  1+1 >= rownum()";
execute stmt;
a
1
2
execute stmt;
a
1
2
deallocate prepare stmt;
# expensive (no opt)
select * from (select a from t1 where a < 1000) as tt where  (select max(a) from t1) >= rownum();
a
1
2
3
4
5
explain extended select * from (select a from t1 where a < 1000) as tt where  (select max(a) from t1) >= rownum();
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
3	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	
2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
Warnings:
Note	1003	/* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 limit 5) `tt` where (/* select#3 */ select max(`test`.`t1`.`a`) from `test`.`t1`) >= rownum() limit 5
prepare stmt from "select * from (select a from t1 where a < 1000) as tt where  (select max(a) from t1) >= rownum()";
execute stmt;
a
1
2
3
4
5
execute stmt;
a
1
2
3
4
5
deallocate prepare stmt;
drop table t1;
#
# Table value constructors
#
values ("first row"),("next row is 3"),(rownum()),("next row is 5"),(rownum());
first row
first row
next row is 3
3
next row is 5
5