为什么第一个INSERT要经过table2。请注意,table2.col_1不是NULL。它不会为col_1插入NULL,但会神奇地将NULL值转换为空字符串。我正在使用MySQL版本5.5.28。谢谢MySQL在NOT NULL列中插入带有NULL值的记录
mysql> DROP TABLE IF EXISTS table1, table2;
Query OK, 0 rows affected (0.01 sec)
mysql> CREATE TABLE IF NOT EXISTS table1 (
-> id INT UNSIGNED NOT NULL AUTO_INCREMENT ,
-> col_1 VARCHAR(45) NOT NULL ,
-> col_2 VARCHAR(45) NOT NULL ,
-> PRIMARY KEY (`id`))
-> ENGINE = InnoDB;
Query OK, 0 rows affected (0.01 sec)
mysql> CREATE TABLE table2 LIKE table1;
Query OK, 0 rows affected (0.00 sec)
mysql> INSERT INTO table1 (id, col_1, col_2) VALUES (NULL, "xxx","yyy");
Query OK, 1 row affected (0.00 sec)
mysql> INSERT INTO table2 (id, col_1, col_2) SELECT NULL, NULL, col_2 FROM table1 WHERE id=1;
Query OK, 1 row affected, 1 warning (0.00 sec)
Records: 1 Duplicates: 0 Warnings: 1
mysql> SHOW WARNINGS;
+---------+------+-------------------------------+
| Level | Code | Message |
+---------+------+-------------------------------+
| Warning | 1048 | Column 'col_1' cannot be null |
+---------+------+-------------------------------+
1 row in set (0.00 sec)
mysql> SELECT * FROM table2;
+----+-------+-------+
| id | col_1 | col_2 |
+----+-------+-------+
| 1 | | yyy |
+----+-------+-------+
1 row in set (0.00 sec)
mysql> INSERT INTO table2 (id, col_1, col_2) VALUES(NULL, NULL, "zzz");
ERROR 1048 (23000): Column 'col_1' cannot be null
mysql> SELECT * FROM table2;
+----+-------+-------+
| id | col_1 | col_2 |
+----+-------+-------+
| 1 | | yyy |
+----+-------+-------+
1 row in set (0.00 sec)
也许它插入'NULL'字符串,而不是空(*不*) – 2013-04-09 15:00:08
奇怪了,我做的是相同的,我得到了插入空...也许你可以在绑定值时指定PDO :: PARAM_INT? – Sebas 2013-04-09 15:05:58
@JW请解释一下。我只是编辑了原始帖子,以显示如果插入由SELECT提供,它只插入一行。 – user1032531 2013-04-09 15:06:02