drop table if exists t1; select (1,2,3) IN ((3,2,3), (1,2,3), (1,3,3)); (1,2,3) IN ((3,2,3), (1,2,3), (1,3,3)) 1 select row(10,2,3) IN (row(3,2,3), row(1,2,3), row(1,3,3)); row(10,2,3) IN (row(3,2,3), row(1,2,3), row(1,3,3)) 0 select row(1,2,3) IN (row(3,NULL,3), row(1,2,3), row(1,3,3)); row(1,2,3) IN (row(3,NULL,3), row(1,2,3), row(1,3,3)) 1 select row(10,2,3) IN (row(3,NULL,3), row(1,2,3), row(1,3,3)); row(10,2,3) IN (row(3,NULL,3), row(1,2,3), row(1,3,3)) 0 select row('a',1.5,3) IN (row(1,2,3), row('a',1.5,3), row('a','a','a')); row('a',1.5,3) IN (row(1,2,3), row('a',1.5,3), row('a','a','a')) 1 Warnings: Warning 1292 Truncated incorrect DECIMAL value: 'a' Warning 1292 Truncated incorrect INTEGER value: 'a' select row('a',0,3) IN (row(3,2,3), row('a','a','3'), row(1,3,3)); row('a',0,3) IN (row(3,2,3), row('a','a','3'), row(1,3,3)) 1 Warnings: Warning 1292 Truncated incorrect INTEGER value: 'a' select row('a',0,3) IN (row(3,2,3), row('a','0','3'), row(1,3,3)); row('a',0,3) IN (row(3,2,3), row('a','0','3'), row(1,3,3)) 1 select row('a',1.5,3) IN (row(3,NULL,3), row('a',1.5,3), row(1,3,3)); row('a',1.5,3) IN (row(3,NULL,3), row('a',1.5,3), row(1,3,3)) 1 select row('b',1.5,3) IN (row(3,NULL,3), row('a',1.5,3), row(1,3,3)); row('b',1.5,3) IN (row(3,NULL,3), row('a',1.5,3), row(1,3,3)) 0 select row('b',1.5,3) IN (row('b',NULL,3), row('a',1.5,3), row(1,3,3)); row('b',1.5,3) IN (row('b',NULL,3), row('a',1.5,3), row(1,3,3)) NULL select row('b',1.5,3) IN (row('b',NULL,4), row('a',1.5,3), row(1,3,3)); row('b',1.5,3) IN (row('b',NULL,4), row('a',1.5,3), row(1,3,3)) 0 select (1,2,(3,4)) IN ((3,2,(3,4)), (1,2,(3,4))); (1,2,(3,4)) IN ((3,2,(3,4)), (1,2,(3,4))) 1 select row(1,2,row(3,4)) IN (row(3,2,row(3,4)), row(1,2,4)); ERROR 21000: Operand should contain 2 column(s) select row(1,2,row(3,4)) IN (row(3,2,row(3,4)), row(1,2,row(3,NULL))); row(1,2,row(3,4)) IN (row(3,2,row(3,4)), row(1,2,row(3,NULL))) NULL explain extended select row(1,2,row(3,4)) IN (row(3,2,row(3,4)), row(1,2,row(3,NULL))); id select_type table type possible_keys key key_len ref rows filtered Extra 1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used Warnings: Note 1003 select ((1,2,(3,4)) in ((3,2,(3,4)),(1,2,(3,NULL)))) AS `row(1,2,row(3,4)) IN (row(3,2,row(3,4)), row(1,2,row(3,NULL)))` SELECT (1,2,3)=(0,NULL,3); (1,2,3)=(0,NULL,3) 0 SELECT (1,2,3)=(1,NULL,3); (1,2,3)=(1,NULL,3) NULL SELECT (1,2,3)=(1,NULL,0); (1,2,3)=(1,NULL,0) 0 SELECT ROW(1,2,3)=ROW(1,2,3); ROW(1,2,3)=ROW(1,2,3) 1 SELECT ROW(2,2,3)=ROW(1+1,2,3); ROW(2,2,3)=ROW(1+1,2,3) 1 SELECT ROW(1,2,3)=ROW(1+1,2,3); ROW(1,2,3)=ROW(1+1,2,3) 0 SELECT ROW(1,2,3)<ROW(1+1,2,3); ROW(1,2,3)<ROW(1+1,2,3) 1 SELECT ROW(1,2,3)>ROW(1+1,2,3); ROW(1,2,3)>ROW(1+1,2,3) 0 SELECT ROW(1,2,3)<=ROW(1+1,2,3); ROW(1,2,3)<=ROW(1+1,2,3) 1 SELECT ROW(1,2,3)>=ROW(1+1,2,3); ROW(1,2,3)>=ROW(1+1,2,3) 0 SELECT ROW(1,2,3)<>ROW(1+1,2,3); ROW(1,2,3)<>ROW(1+1,2,3) 1 SELECT ROW(NULL,2,3)=ROW(NULL,2,3); ROW(NULL,2,3)=ROW(NULL,2,3) NULL SELECT ROW(NULL,2,3)<=>ROW(NULL,2,3); ROW(NULL,2,3)<=>ROW(NULL,2,3) 1 SELECT ROW(1,2,ROW(3,4,5))=ROW(1,2,ROW(3,4,5)); ROW(1,2,ROW(3,4,5))=ROW(1,2,ROW(3,4,5)) 1 SELECT ROW('test',2,3.33)=ROW('test',2,3.33); ROW('test',2,3.33)=ROW('test',2,3.33) 1 SELECT ROW('test',2,3.33)=ROW('test',2,3.33,4); ERROR 21000: Operand should contain 3 column(s) SELECT ROW('test',2,ROW(3,33))=ROW('test',2,ROW(3,33)); ROW('test',2,ROW(3,33))=ROW('test',2,ROW(3,33)) 1 SELECT ROW('test',2,ROW(3,33))=ROW('test',2,ROW(3,3)); ROW('test',2,ROW(3,33))=ROW('test',2,ROW(3,3)) 0 SELECT ROW('test',2,ROW(3,33))=ROW('test',2,ROW(3,NULL)); ROW('test',2,ROW(3,33))=ROW('test',2,ROW(3,NULL)) NULL SELECT ROW('test',2,ROW(3,33))=ROW('test',2,4); ERROR 21000: Operand should contain 2 column(s) create table t1 ( a int, b int, c int); insert into t1 values (1,2,3), (2,3,1), (3,2,1), (1,2,NULL); select * from t1 where ROW(1,2,3)=ROW(a,b,c); a b c 1 2 3 select * from t1 where ROW(0,2,3)=ROW(a,b,c); a b c select * from t1 where ROW(1,2,3)<ROW(a,b,c); a b c 2 3 1 3 2 1 select ROW(a,2,3) IN(row(1,b,c), row(2,3,1)) from t1; ROW(a,2,3) IN(row(1,b,c), row(2,3,1)) 1 0 0 NULL select ROW(c,2,3) IN(row(1,b,a), row(2,3,1)) from t1; ROW(c,2,3) IN(row(1,b,a), row(2,3,1)) 0 0 1 NULL select ROW(a,b,c) IN(row(1,2,3), row(3,2,1)) from t1; ROW(a,b,c) IN(row(1,2,3), row(3,2,1)) 1 0 1 NULL select ROW(1,2,3) IN(row(a,b,c), row(1,2,3)) from t1; ROW(1,2,3) IN(row(a,b,c), row(1,2,3)) 1 1 1 1 drop table t1; select ROW(1,1); ERROR 21000: Operand should contain 1 column(s) create table t1 (i int); select 1 from t1 where ROW(1,1); ERROR 21000: Operand should contain 1 column(s) select count(*) from t1 order by ROW(1,1); ERROR 21000: Operand should contain 1 column(s) select count(*) from t1 having (1,1) order by i; ERROR 21000: Operand should contain 1 column(s) drop table t1; create table t1 (a int, b int); insert into t1 values (1, 4); insert into t1 values (10, 40); insert into t1 values (1, 4); insert into t1 values (10, 43); insert into t1 values (1, 4); insert into t1 values (10, 41); insert into t1 values (1, 4); insert into t1 values (10, 43); insert into t1 values (1, 4); select a, MAX(b), (1, MAX(b)) = (1, 4) from t1 group by a; a MAX(b) (1, MAX(b)) = (1, 4) 1 4 1 10 43 0 drop table t1; SELECT ROW(2,10) <=> ROW(3,4); ROW(2,10) <=> ROW(3,4) 0 SELECT ROW(NULL,10) <=> ROW(3,NULL); ROW(NULL,10) <=> ROW(3,NULL) 0 SELECT ROW(1,1,1) = ROW(1,1,1) as `1`, ROW(1,1,1) = ROW(1,2,1) as `0`, ROW(1,NULL,1) = ROW(2,2,1) as `0`, ROW(1,NULL,1) = ROW(1,2,2) as `0`, ROW(1,NULL,1) = ROW(1,2,1) as `null` ; 1 0 0 0 null 1 0 0 0 NULL select row(NULL,1)=(2,0); row(NULL,1)=(2,0) 0 CREATE TABLE t1 (a int, b int, PRIMARY KEY (a,b)); INSERT INTO t1 VALUES (1,1), (2,1), (3,1), (1,2), (3,2), (3,3); EXPLAIN SELECT * FROM t1 WHERE a=3 AND b=2; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 const PRIMARY PRIMARY 8 const,const 1 Using index EXPLAIN SELECT * FROM t1 WHERE (a,b)=(3,2); id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 const PRIMARY PRIMARY 8 const,const 1 Using index SELECT * FROM t1 WHERE a=3 and b=2; a b 3 2 SELECT * FROM t1 WHERE (a,b)=(3,2); a b 3 2 CREATE TABLE t2 (a int, b int, c int, PRIMARY KEY (a,b,c)); INSERT INTO t2 VALUES (1,1,2), (3,1,3), (1,2,2), (4,4,2), (1,1,1), (3,1,1), (1,2,1); EXPLAIN SELECT * FROM t1,t2 WHERE t1.a=t2.a AND t1.b=t2.b; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index PRIMARY PRIMARY 8 NULL 6 Using index 1 SIMPLE t2 ref PRIMARY PRIMARY 8 test.t1.a,test.t1.b 1 Using index EXPLAIN SELECT * FROM t1,t2 WHERE (t1.a,t1.b)=(t2.a,t2.b); id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index PRIMARY PRIMARY 8 NULL 6 Using index 1 SIMPLE t2 ref PRIMARY PRIMARY 8 test.t1.a,test.t1.b 1 Using index SELECT * FROM t1,t2 WHERE t1.a=t2.a and t1.b=t2.b; a b a b c 1 1 1 1 1 1 1 1 1 2 1 2 1 2 1 1 2 1 2 2 3 1 3 1 1 3 1 3 1 3 SELECT * FROM t1,t2 WHERE (t1.a,t1.b)=(t2.a,t2.b); a b a b c 1 1 1 1 1 1 1 1 1 2 1 2 1 2 1 1 2 1 2 2 3 1 3 1 1 3 1 3 1 3 EXPLAIN SELECT * FROM t1,t2 WHERE t1.a=t2.a AND t1.b=2; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index PRIMARY PRIMARY 8 NULL 6 Using where; Using index 1 SIMPLE t2 ref PRIMARY PRIMARY 4 test.t1.a 1 Using index EXPLAIN SELECT * FROM t1,t2 WHERE (t1.a,t1.b)=(t2.a,2); id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index PRIMARY PRIMARY 8 NULL 6 Using where; Using index 1 SIMPLE t2 ref PRIMARY PRIMARY 4 test.t1.a 1 Using index SELECT * FROM t1,t2 WHERE t1.a=1 and t1.b=t2.b; a b a b c 1 1 1 1 2 1 1 3 1 3 1 2 1 2 2 1 1 1 1 1 1 1 3 1 1 1 2 1 2 1 SELECT * FROM t1,t2 WHERE (t1.a,t1.b)=(t2.a,2); a b a b c 1 2 1 1 1 1 2 1 1 2 1 2 1 2 1 1 2 1 2 2 3 2 3 1 1 3 2 3 1 3 EXPLAIN EXTENDED SELECT * FROM t1,t2 WHERE (t1.a,t1.b)=(t2.a,t2.b+1); id select_type table type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 index PRIMARY PRIMARY 8 NULL 6 100.00 Using index 1 SIMPLE t2 ref PRIMARY PRIMARY 4 test.t1.a 1 100.00 Using where; Using index Warnings: Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`c` AS `c` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`a` = `test`.`t1`.`a`) and (`test`.`t1`.`b` = (`test`.`t2`.`b` + 1))) SELECT * FROM t1,t2 WHERE (t1.a,t1.b)=(t2.a,t2.b+1); a b a b c 1 2 1 1 1 1 2 1 1 2 3 2 3 1 1 3 2 3 1 3 EXPLAIN EXTENDED SELECT * FROM t1,t2 WHERE (t1.a-1,t1.b)=(t2.a-1,t2.b+1); id select_type table type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 index NULL PRIMARY 8 NULL 6 100.00 Using index 1 SIMPLE t2 index NULL PRIMARY 12 NULL 7 100.00 Using where; Using index Warnings: Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`c` AS `c` from `test`.`t1` join `test`.`t2` where (((`test`.`t1`.`a` - 1) = (`test`.`t2`.`a` - 1)) and (`test`.`t1`.`b` = (`test`.`t2`.`b` + 1))) SELECT * FROM t1,t2 WHERE (t1.a-1,t1.b)=(t2.a-1,t2.b+1); a b a b c 1 2 1 1 2 3 2 3 1 3 1 2 1 1 1 3 2 3 1 1 EXPLAIN SELECT * FROM t2 WHERE a=3 AND b=2; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t2 ref PRIMARY PRIMARY 8 const,const 1 Using index EXPLAIN SELECT * FROM t2 WHERE (a,b)=(3,2); id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t2 ref PRIMARY PRIMARY 8 const,const 1 Using index SELECT * FROM t2 WHERE a=3 and b=2; a b c SELECT * FROM t2 WHERE (a,b)=(3,2); a b c EXPLAIN SELECT * FROM t1,t2 WHERE t2.a=t1.a AND t2.b=2 AND t2.c=1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index PRIMARY PRIMARY 8 NULL 6 Using index 1 SIMPLE t2 eq_ref PRIMARY PRIMARY 12 test.t1.a,const,const 1 Using index EXPLAIN EXTENDED SELECT * FROM t1,t2 WHERE (t2.a,(t2.b,t2.c))=(t1.a,(2,1)); id select_type table type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 index PRIMARY PRIMARY 8 NULL 6 100.00 Using index 1 SIMPLE t2 eq_ref PRIMARY PRIMARY 12 test.t1.a,const,const 1 100.00 Using index Warnings: Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`c` AS `c` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`c` = 1) and (`test`.`t2`.`b` = 2) and (`test`.`t2`.`a` = `test`.`t1`.`a`)) SELECT * FROM t1,t2 WHERE (t2.a,(t2.b,t2.c))=(t1.a,(2,1)); a b a b c 1 1 1 2 1 1 2 1 2 1 EXPLAIN EXTENDED SELECT * FROM t1,t2 WHERE t2.a=t1.a AND (t2.b,t2.c)=(2,1); id select_type table type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 index PRIMARY PRIMARY 8 NULL 6 100.00 Using index 1 SIMPLE t2 eq_ref PRIMARY PRIMARY 12 test.t1.a,const,const 1 100.00 Using index Warnings: Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`c` AS `c` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`c` = 1) and (`test`.`t2`.`b` = 2) and (`test`.`t2`.`a` = `test`.`t1`.`a`)) SELECT * FROM t1,t2 WHERE t2.a=t1.a AND (t2.b,t2.c)=(2,1); a b a b c 1 1 1 2 1 1 2 1 2 1 DROP TABLE t1,t2; CREATE TABLE t1( a int, b int, c int, d int, e int, f int, g int, h int, PRIMARY KEY (a,b,c,d,e,f,g) ); INSERT INTO t1 VALUES (1,2,3,4,5,6,7,99); SELECT h FROM t1 WHERE (a,b,c,d,e,f,g)=(1,2,3,4,5,6,7); h 99 SET @x:= (SELECT h FROM t1 WHERE (a,b,c,d,e,f,g)=(1,2,3,4,5,6,7)); SELECT @x; @x 99 DROP TABLE t1;