一.mysql 5.6
mysql> select version();
+------------+
| version() |
+------------+
| 5.6.16-log |
1.無主鍵
mysql> create table t02(a int,b int)engine=innodb;
Query OK, 0 rows affected (0.01 sec)
mysql> insert into t02 values(1,1),(0,1);
Query OK, 2 rows affected (0.00 sec)
Records: 2 Duplicates: 0 Warnings: 0
mysql> select * from t02;
+------+------+
| a | b |
+------+------+
| 1 | 1 |
| 0 | 1 |
+------+------+
2 rows in set (0.00 sec)
mysql> update t02 set a=1 and b=2;
Query OK, 1 row affected (0.00 sec)
Rows matched: 2 Changed: 1 Warnings: 0
mysql> select * from t02;
+------+------+
| a | b |
+------+------+
| 0 | 1 |
| 0 | 1 |
+------+------+
2 rows in set (0.00 sec)
mysql> create table t03(id int,a int,b int,primary key(id))engine=innodb;
Query OK, 0 rows affected (0.01 sec)
mysql> insert into t03 values(1,1,1),(3,0,1);
Query OK, 2 rows affected (0.00 sec)
Records: 2 Duplicates: 0 Warnings: 0
mysql> select * from t03;
+----+------+------+
| id | a | b |
+----+------+------+
| 1 | 1 | 1 |
| 3 | 0 | 1 |
+----+------+------+
2 rows in set (0.00 sec)
mysql> update t03 set a=1 and b=2;
Query OK, 1 row affected (0.01 sec)
Rows matched: 2 Changed: 1 Warnings: 0
mysql> select * from t03;
+----+------+------+
| id | a | b |
+----+------+------+
| 1 | 0 | 1 |
| 3 | 0 | 1 |
+----+------+------+
2 rows in set (0.00 sec)
2.有主鍵
mysql> insert into t02 values(1,1),(0,1);
Query OK, 2 rows affected (0.00 sec)
Records: 2 Duplicates: 0 Warnings: 0
mysql> select * from t02;
+------+------+
| a | b |
+------+------+
| 1 | 1 |
| 0 | 1 |
+------+------+
2 rows in set (0.00 sec)
二. mysql 5.5
mysql> select version();
+------------+
| version() |
+------------+
| 5.5.36-log |
1.無主鍵
mysql> create table t02(a int,b int)engine=innodb;
Query OK, 0 rows affected (0.01 sec)
mysql> insert into t02 values(1,1),(0,1),(3,2);
mysql> update t02 set a=1 and b=2;
Query OK, 1 row affected (0.00 sec)
Rows matched: 2 Changed: 1 Warnings: 0
mysql> select * from t02;
+------+------+
| a | b |
+------+------+
| 0 | 1 |
| 0 | 1 |
+------+------+
2 rows in set (0.00 sec)
mysql> truncate table t02 ;
Query OK, 0 rows affected (0.00 sec)
mysql> insert into t02 values(1,1),(0,1),(3,2);
Query OK, 3 rows affected (0.00 sec)
Records: 3 Duplicates: 0 Warnings: 0
mysql> update t02 set a=1 and b=2;
Query OK, 2 rows affected (0.00 sec)
Rows matched: 3 Changed: 2 Warnings: 0
mysql> select * from t02;
+------+------+
| a | b |
+------+------+
| 0 | 1 |
| 0 | 1 |
| 1 | 2 |
+------+------+
3 rows in set (0.00 sec)
2.有主鍵
mysql> create table t03(id int,a int,b int,primary key(id))engine=innodb;
Query OK, 0 rows affected (0.01 sec)
mysql> insert into t03 values(1,1,1),(3,0,1);
Query OK, 2 rows affected (0.00 sec)
Records: 2 Duplicates: 0 Warnings: 0
mysql> select * from t03;
+----+------+------+
| id | a | b |
+----+------+------+
| 1 | 1 | 1 |
| 3 | 0 | 1 |
+----+------+------+
2 rows in set (0.00 sec)
mysql> update t03 set a=1 and b=2;
Query OK, 1 row affected (0.00 sec)
Rows matched: 2 Changed: 1 Warnings: 0
mysql> select * from t03;
+----+------+------+
| id | a | b |
+----+------+------+
| 1 | 0 | 1 |
| 3 | 0 | 1 |
+----+------+------+
2 rows in set (0.00 sec)
mysql> truncate table t03;
Query OK, 0 rows affected (0.00 sec)
mysql> insert into t03 values(1,1,1),(3,0,1),(2,3,5),(5,9,5);
Query OK, 4 rows affected (0.00 sec)
Records: 4 Duplicates: 0 Warnings: 0
mysql> select * from t03 ;
+----+------+------+
| id | a | b |
+----+------+------+
| 1 | 1 | 1 |
| 2 | 3 | 5 |
| 3 | 0 | 1 |
| 5 | 9 | 5 |
+----+------+------+
4 rows in set (0.00 sec)
mysql> update t03 set a=1 and b=2;
Query OK, 3 rows affected (0.00 sec)
Rows matched: 4 Changed: 3 Warnings: 0
mysql> select * from t03 ;
+----+------+------+
| id | a | b |
+----+------+------+
| 1 | 0 | 1 |
| 2 | 0 | 5 |
| 3 | 0 | 1 |
| 5 | 0 | 5 |
+----+------+------+
4 rows in set (0.00 sec)
mysql> update t02 set a=7 and b=7;
Query OK, 1 row affected (0.00 sec)
Rows matched: 3 Changed: 1 Warnings: 0
mysql> select * from t02;
+------+------+
| a | b |
+------+------+
| 0 | 1 |
| 0 | 1 |
| 1 | 7 |
+------+------+
總結：這個update（ update t03 set a=1 and b=2;） 千萬不要當成是 update t03 set a=1,b=2;
update t03 set a=1 and b=2; 其實是update t03 set a=(1 and b=2);
#其實就是對列 a 賦值啊，1 and b=2 把列b=2 的再and 1 取 and 之後的邏輯值(0或1)，哈哈，是不是一不小心就踩進坑了啊,眼睛睜大了哈……