join_nested.result

来自「视频监控网络部分的协议ddns,的模块的实现代码,请大家大胆指正.」· RESULT 代码 · 共 1,747 行 · 第 1/4 页

FROM t0,t1
LEFT JOIN                
( 
t2
LEFT JOIN              
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5 
LEFT JOIN 
( 
(t6, t7)
LEFT JOIN 
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b 
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2),
t9
WHERE t0.a=1 AND
t0.b=t1.b AND          
(t2.a >= 4 OR t2.c IS NULL) AND
(t3.a < 5 OR t3.c IS NULL) AND
(t3.b=t4.b OR t3.c IS NULL OR t4.c IS NULL) AND
(t5.a >=2 OR t5.c IS NULL) AND
(t6.a >=4 OR t6.c IS NULL) AND
(t7.a <= 2 OR t7.c IS NULL) AND
(t8.a < 1 OR t8.c IS NULL) AND
(t8.b=t9.b OR t8.c IS NULL) AND
(t9.a=1);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	3	Using where
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	Using where
1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	Using where
1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	2	Using where
1	SIMPLE	t5	ALL	NULL	NULL	NULL	NULL	3	Using where
1	SIMPLE	t7	ALL	NULL	NULL	NULL	NULL	2	Using where
1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	3	Using where
1	SIMPLE	t8	ALL	NULL	NULL	NULL	NULL	2	Using where
1	SIMPLE	t9	ALL	NULL	NULL	NULL	NULL	3	Using where
Warnings:
Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on(((`test`.`t4`.`b` = `test`.`t2`.`b`) and (`test`.`t3`.`a` = 1))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on(((`test`.`t8`.`b` = `test`.`t5`.`b`) and (`test`.`t6`.`b` < 10)))) on(((`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t6`.`b` >= 2)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and ((`test`.`t5`.`b` = `test`.`t0`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
CREATE INDEX idx_b ON t4(b);
CREATE INDEX idx_b ON t5(b);
EXPLAIN EXTENDED
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b,t9.a,t9.b
FROM t0,t1
LEFT JOIN                
( 
t2
LEFT JOIN              
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5 
LEFT JOIN 
( 
(t6, t7)
LEFT JOIN 
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b 
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2),
t9
WHERE t0.a=1 AND
t0.b=t1.b AND          
(t2.a >= 4 OR t2.c IS NULL) AND
(t3.a < 5 OR t3.c IS NULL) AND
(t3.b=t4.b OR t3.c IS NULL OR t4.c IS NULL) AND
(t5.a >=2 OR t5.c IS NULL) AND
(t6.a >=4 OR t6.c IS NULL) AND
(t7.a <= 2 OR t7.c IS NULL) AND
(t8.a < 1 OR t8.c IS NULL) AND
(t8.b=t9.b OR t8.c IS NULL) AND
(t9.a=1);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	3	Using where
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	Using where
1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	Using where
1	SIMPLE	t4	ref	idx_b	idx_b	5	test.t2.b	2	Using where
1	SIMPLE	t5	ALL	idx_b	NULL	NULL	NULL	3	Using where
1	SIMPLE	t7	ALL	NULL	NULL	NULL	NULL	2	Using where
1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	3	Using where
1	SIMPLE	t8	ALL	NULL	NULL	NULL	NULL	2	Using where
1	SIMPLE	t9	ALL	NULL	NULL	NULL	NULL	3	Using where
Warnings:
Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on(((`test`.`t4`.`b` = `test`.`t2`.`b`) and (`test`.`t3`.`a` = 1))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on(((`test`.`t8`.`b` = `test`.`t5`.`b`) and (`test`.`t6`.`b` < 10)))) on(((`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t6`.`b` >= 2)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and ((`test`.`t5`.`b` = `test`.`t0`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
CREATE INDEX idx_b ON t8(b);
EXPLAIN EXTENDED
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b,t9.a,t9.b
FROM t0,t1
LEFT JOIN                
( 
t2
LEFT JOIN              
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5 
LEFT JOIN 
( 
(t6, t7)
LEFT JOIN 
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b 
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2),
t9
WHERE t0.a=1 AND
t0.b=t1.b AND          
(t2.a >= 4 OR t2.c IS NULL) AND
(t3.a < 5 OR t3.c IS NULL) AND
(t3.b=t4.b OR t3.c IS NULL OR t4.c IS NULL) AND
(t5.a >=2 OR t5.c IS NULL) AND
(t6.a >=4 OR t6.c IS NULL) AND
(t7.a <= 2 OR t7.c IS NULL) AND
(t8.a < 1 OR t8.c IS NULL) AND
(t8.b=t9.b OR t8.c IS NULL) AND
(t9.a=1);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	3	Using where
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	Using where
1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	Using where
1	SIMPLE	t4	ref	idx_b	idx_b	5	test.t2.b	2	Using where
1	SIMPLE	t5	ALL	idx_b	NULL	NULL	NULL	3	Using where
1	SIMPLE	t7	ALL	NULL	NULL	NULL	NULL	2	Using where
1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	3	Using where
1	SIMPLE	t8	ref	idx_b	idx_b	5	test.t5.b	2	Using where
1	SIMPLE	t9	ALL	NULL	NULL	NULL	NULL	3	Using where
Warnings:
Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on(((`test`.`t4`.`b` = `test`.`t2`.`b`) and (`test`.`t3`.`a` = 1))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on(((`test`.`t8`.`b` = `test`.`t5`.`b`) and (`test`.`t6`.`b` < 10)))) on(((`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t6`.`b` >= 2)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and ((`test`.`t5`.`b` = `test`.`t0`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
CREATE INDEX idx_b ON t1(b);
CREATE INDEX idx_a ON t0(a);
EXPLAIN EXTENDED
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b,t9.a,t9.b
FROM t0,t1
LEFT JOIN                
( 
t2
LEFT JOIN              
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5 
LEFT JOIN 
( 
(t6, t7)
LEFT JOIN 
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b 
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2),
t9
WHERE t0.a=1 AND
t0.b=t1.b AND          
(t2.a >= 4 OR t2.c IS NULL) AND
(t3.a < 5 OR t3.c IS NULL) AND
(t3.b=t4.b OR t3.c IS NULL OR t4.c IS NULL) AND
(t5.a >=2 OR t5.c IS NULL) AND
(t6.a >=4 OR t6.c IS NULL) AND
(t7.a <= 2 OR t7.c IS NULL) AND
(t8.a < 1 OR t8.c IS NULL) AND
(t8.b=t9.b OR t8.c IS NULL) AND
(t9.a=1);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t0	ref	idx_a	idx_a	5	const	1	Using where
1	SIMPLE	t1	ref	idx_b	idx_b	5	test.t0.b	2	Using where
1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	Using where
1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	Using where
1	SIMPLE	t4	ref	idx_b	idx_b	5	test.t2.b	2	Using where
1	SIMPLE	t5	ALL	idx_b	NULL	NULL	NULL	3	Using where
1	SIMPLE	t7	ALL	NULL	NULL	NULL	NULL	2	Using where
1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	3	Using where
1	SIMPLE	t8	ref	idx_b	idx_b	5	test.t5.b	2	Using where
1	SIMPLE	t9	ALL	NULL	NULL	NULL	NULL	3	Using where
Warnings:
Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on(((`test`.`t4`.`b` = `test`.`t2`.`b`) and (`test`.`t3`.`a` = 1))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on(((`test`.`t8`.`b` = `test`.`t5`.`b`) and (`test`.`t6`.`b` < 10)))) on(((`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t6`.`b` >= 2)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and ((`test`.`t5`.`b` = `test`.`t0`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b,t9.a,t9.b
FROM t0,t1
LEFT JOIN                
( 
t2
LEFT JOIN              
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5 
LEFT JOIN 
( 
(t6, t7)
LEFT JOIN 
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b 
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2),
t9
WHERE t0.a=1 AND
t0.b=t1.b AND          
(t2.a >= 4 OR t2.c IS NULL) AND
(t3.a < 5 OR t3.c IS NULL) AND
(t3.b=t4.b OR t3.c IS NULL OR t4.c IS NULL) AND
(t5.a >=2 OR t5.c IS NULL) AND
(t6.a >=4 OR t6.c IS NULL) AND
(t7.a <= 2 OR t7.c IS NULL) AND
(t8.a < 1 OR t8.c IS NULL) AND
(t8.b=t9.b OR t8.c IS NULL) AND
(t9.a=1);
a	b	a	b	a	b	a	b	a	b	a	b	a	b	a	b	a	b	a	b
1	2	2	2	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	1	1
1	2	3	2	4	2	1	2	3	2	3	1	6	2	1	1	NULL	NULL	1	1
1	2	3	2	4	2	1	2	3	2	3	3	NULL	NULL	NULL	NULL	NULL	NULL	1	1
1	2	3	2	4	2	1	2	4	2	3	1	6	2	1	1	NULL	NULL	1	1
1	2	3	2	4	2	1	2	4	2	3	3	NULL	NULL	NULL	NULL	NULL	NULL	1	1
1	2	3	2	5	3	NULL	NULL	NULL	NULL	3	1	6	2	1	1	NULL	NULL	1	1
1	2	3	2	5	3	NULL	NULL	NULL	NULL	3	3	NULL	NULL	NULL	NULL	NULL	NULL	1	1
1	2	2	2	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	1	2
1	2	3	2	4	2	1	2	3	2	3	1	6	2	1	1	NULL	NULL	1	2
1	2	3	2	4	2	1	2	3	2	2	2	6	2	2	2	0	2	1	2
1	2	3	2	4	2	1	2	3	2	3	3	NULL	NULL	NULL	NULL	NULL	NULL	1	2
1	2	3	2	4	2	1	2	4	2	3	1	6	2	1	1	NULL	NULL	1	2
1	2	3	2	4	2	1	2	4	2	2	2	6	2	2	2	0	2	1	2
1	2	3	2	4	2	1	2	4	2	3	3	NULL	NULL	NULL	NULL	NULL	NULL	1	2
1	2	3	2	5	3	NULL	NULL	NULL	NULL	3	1	6	2	1	1	NULL	NULL	1	2
1	2	3	2	5	3	NULL	NULL	NULL	NULL	2	2	6	2	2	2	0	2	1	2
1	2	3	2	5	3	NULL	NULL	NULL	NULL	3	3	NULL	NULL	NULL	NULL	NULL	NULL	1	2
SELECT t2.a,t2.b
FROM t2;
a	b
3	3
4	2
5	3
SELECT t3.a,t3.b
FROM t3;
a	b
1	2
2	2
SELECT t2.a,t2.b,t3.a,t3.b
FROM t2 LEFT JOIN t3 ON t2.b=t3.b
WHERE t2.a = 4 OR (t2.a > 4 AND t3.a IS NULL);
a	b	a	b
4	2	1	2
4	2	2	2
5	3	NULL	NULL
SELECT t2.a,t2.b,t3.a,t3.b
FROM t2 LEFT JOIN (t3) ON t2.b=t3.b
WHERE t2.a = 4 OR (t2.a > 4 AND t3.a IS NULL);
a	b	a	b
4	2	1	2
4	2	2	2
5	3	NULL	NULL
ALTER TABLE t3
CHANGE COLUMN a a1 int,
CHANGE COLUMN c c1 int;
SELECT t2.a,t2.b,t3.a1,t3.b
FROM t2 LEFT JOIN t3 ON t2.b=t3.b
WHERE t2.a = 4 OR (t2.a > 4 AND t3.a1 IS NULL);
a	b	a1	b
4	2	1	2
4	2	2	2
5	3	NULL	NULL
SELECT t2.a,t2.b,t3.a1,t3.b
FROM t2 NATURAL LEFT JOIN t3
WHERE t2.a = 4 OR (t2.a > 4 AND t3.a1 IS NULL);
a	b	a1	b
4	2	1	2
4	2	2	2
5	3	NULL	NULL
DROP TABLE t0,t1,t2,t3,t4,t5,t6,t7,t8,t9;
CREATE TABLE t1 (a int);
CREATE TABLE t2 (a int);
CREATE TABLE t3 (a int);
INSERT INTO t1 VALUES (1);
INSERT INTO t2 VALUES (2);
INSERT INTO t3 VALUES (2);
INSERT INTO t1 VALUES (2);
SELECT * FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.a=t3.a) ON t1.a=t3.a;
a	a	a
1	NULL	NULL
2	2	2
SELECT * FROM t1 LEFT JOIN t2 LEFT JOIN t3 ON t2.a=t3.a ON t1.a=t3.a;
a	a	a
1	NULL	NULL
2	2	2
DELETE FROM t1 WHERE a=2;
SELECT * FROM t1 LEFT JOIN t2 LEFT JOIN t3 ON t2.a=t3.a ON t1.a=t3.a;
a	a	a
1	NULL	NULL
DELETE FROM t2;
SELECT * FROM t1 LEFT JOIN t2 LEFT JOIN t3 ON t2.a=t3.a ON t1.a=t3.a;
a	a	a
1	NULL	NULL
DROP TABLE t1,t2,t3;
CREATE TABLE t1(a int, key (a));
CREATE TABLE t2(b int, key (b));
CREATE TABLE t3(c int, key (c));
INSERT INTO t1 VALUES (NULL), (0), (1), (2), (3), (4), (5), (6), (7), (8), (9),
(10), (11), (12), (13), (14), (15), (16), (17), (18), (19);
INSERT INTO t2 VALUES (NULL), (0), (1), (2), (3), (4), (5), (6), (7), (8), (9),
(10), (11), (12), (13), (14), (15), (16), (17), (18), (19);
INSERT INTO t3 VALUES (0), (1), (2), (3), (4), (5);
EXPLAIN SELECT a, b, c FROM t1 LEFT JOIN (t2, t3) ON c < 3 and b = c;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	index	NULL	a	5	NULL	21	Using index
1	SIMPLE	t3	index	c	c	5	NULL	6	Using index
1	SIMPLE	t2	ref	b	b	5	test.t3.c	2	Using index
EXPLAIN SELECT a, b, c FROM t1 LEFT JOIN (t2, t3) ON b < 3 and b = c;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	index	NULL	a	5	NULL	21	Using index
1	SIMPLE	t3	index	c	c	5	NULL	6	Using index
1	SIMPLE	t2	ref	b	b	5	test.t3.c	2	Using index
SELECT a, b, c FROM t1 LEFT JOIN (t2, t3) ON b < 3 and b = c;
a	b	c
NULL	0	0
NULL	1	1
NULL	2	2
0	0	0
0	1	1
0	2	2
1	0	0
1	1	1
1	2	2
2	0	0
2	1	1
2	2	2
3	0	0
3	1	1
3	2	2
4	0	0
4	1	1
4	2	2
5	0	0
5	1	1
5	2	2
6	0	0
6	1	1
6	2	2
7	0	0
7	1	1
7	2	2
8	0	0
8	1	1
8	2	2
9	0	0
9	1	1
9	2	2
10	0	0
10	1	1
10	2	2
11	0	0
11	1	1
11	2	2
12	0	0
12	1	1
12	2	2
13	0	0
13	1	1
13	2	2
14	0	0
14	1	1
14	2	2
15	0	0
15	1	1
15	2	2
16	0	0
16	1	1
16	2	2
17	0	0
17	1	1
17	2	2
18	0	0
18	1	1
18	2	2
19	0	0
19	1	1
19	2	2
DELETE FROM t3;
EXPLAIN SELECT a, b, c FROM t1 LEFT JOIN (t2, t3) ON b < 3 and b = c;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	index	NULL	a	5	NULL	21	Using index
1	SIMPLE	t3	index	c	c	5	NULL	0	Using index
1	SIMPLE	t2	ref	b	b	5	test.t3.c	2	Using index
SELECT a, b, c FROM t1 LEFT JOIN (t2, t3) ON b < 3 and b = c;
a	b	c
NULL	NULL	NULL
0	NULL	NULL
1	NULL	NULL
2	NULL	NULL
3	NULL	NULL
4	NULL	NULL
5	NULL	NULL
6	NULL	NULL
7	NULL	NULL
8	NULL	NULL
9	NULL	NULL
10	NULL	NULL
11	NULL	NULL
12	NULL	NULL
13	NULL	NULL
14	NULL	NULL
15	NULL	NULL
16	NULL	NULL
17	NULL	NULL
18	NULL	NULL
19	NULL	NULL
DROP TABLE t1,t2,t3;
CREATE TABLE t1 (c11 int);
CREATE TABLE t2 (c21 int);
CREATE TABLE t3 (c31 int);
INSERT INTO t1 VALUES (4), (5);
SELECT * FROM t1 LEFT JOIN t2 ON c11=c21;
c11	c21
4	NULL
5	NULL
EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON c11=c21;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t2	system	NULL	NULL	NULL	NULL	0	const row not found