MySQL自动将字符串转换为WHERE子句中的整数以获取特定的ID
如果字符串以整数开头，则它将字符串转换为整数，否则不会。让我们首先创建一个-
mysql> create table DemoTable1390 -> ( -> StudentId varchar(20) -> );
使用insert在表中插入一些记录-
mysql> insert into DemoTable1390 values('563_John');
mysql> insert into DemoTable1390 values('1001_Carol_Taylor');
mysql> insert into DemoTable1390 values('David_Miller_789');
mysql> insert into DemoTable1390 values('456_AdamSmith');使用选择显示表中的所有记录-
mysql> select * from DemoTable1390;
这将产生以下输出-
+-------------------+ | StudentId | +-------------------+ | 563_John | | 1001_Carol_Taylor | | David_Miller_789 | | 456_AdamSmith | +-------------------+ 4 rows in set (0.00 sec)
以下是在where子句中自动字符串转换为整数的查询，以获取特定的-
mysql> select * from DemoTable1390 where StudentId=456;
这将产生以下输出-
+---------------+ | StudentId | +---------------+ | 456_AdamSmith | +---------------+ 1 row in set, 4 warnings (0.02 sec)