在MySQL中交换特定的列值
让我们首先创建一个表table-
create table DemoTable1504 -> ( -> Id int, -> FirstName varchar(20) -> );
使用插入命令在表中插入一些记录-
insert into DemoTable1504 values(101,'Chris'); insert into DemoTable1504 values(102,'Bob'); insert into DemoTable1504 values(103,'David'); insert into DemoTable1504 values(104,'Mike');
使用select语句显示表中的所有记录-
select * from DemoTable1504 ;
这将产生以下输出-
+------+-----------+ | Id | FirstName | +------+-----------+ | 101 | Chris | | 102 | Bob | | 103 | David | | 104 | Mike | +------+-----------+ 4 rows in set (0.00 sec)
以下是交换特定列值的查询-
update DemoTable1504 -> set FirstName='Carol' -> where Id=103 -> and FirstName <> 'Carol'; Rows matched: 1 Changed: 1 Warnings: 0
让我们再次检查表记录-
select * from DemoTable1504;
这将产生以下输出-
+------+-----------+ | Id | FirstName | +------+-----------+ | 101 | Chris | | 102 | Bob | | 103 | Carol | | 104 | Mike | +------+-----------+ 4 rows in set (0.00 sec)