MySQL 查询，如果两列相等则删除一行
mysqlmysqli database
使用 DELETE 进行此操作。让我们首先创建一个表 −
mysql> create table DemoTable ( Name varchar(40), Score1 int , Score2 int ); Query OK, 0 rows affected (2.71 sec)
使用 insert 命令在表中插入一些记录 −
mysql> insert into DemoTable values('John',56,76);
Query OK, 1 row affected (0.66 sec)
mysql> insert into DemoTable values('Chris',77,77);
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable values('David',89,98);
Query OK, 1 row affected (0.13 sec)
使用 select 语句显示表中的所有记录 −
mysql> select *from DemoTable;
这将产生以下输出 −
+-------+--------+--------+ | Name | Score1 | Score2 | +-------+--------+--------+ | John | 56 | 76 | | Chris | 77 | 77 | | David | 89 | 98 | +-------+--------+--------+ 3 rows in set (0.00 sec)
以下是当两列相等时删除一行的查询 −
mysql> delete from DemoTable where Score1=Score2; Query OK, 1 row affected (0.29 sec)
让我们再次检查表记录 −
mysql> select *from DemoTable;
这将产生以下输出 −
+-------+--------+--------+ | Name | Score1 | Score2 | +-------+--------+--------+ | John | 56 | 76 | | David | 89 | 98 | +-------+--------+--------+ 2 rows in set (0.00 sec)
