将MySQL表中的空值替换为特定值
让我们首先创建一个表-
create table DemoTable837(Name varchar(100));
使用插入命令在表中插入一些记录-
insert into DemoTable837 values('Chris');
insert into DemoTable837 values('');
insert into DemoTable837 values('Robert');
insert into DemoTable837 values('');
insert into DemoTable837 values('David');使用select语句显示表中的所有记录-
select *from DemoTable837;
这将产生以下输出-
+--------+ | Name | +--------+ | Chris | | | | Robert | | | | David | +--------+ 5 rows in set (0.00 sec)
以下是将空值替换为特定值的查询-
select if(Name='', 'Adam',Name) from DemoTable837;
这将产生以下输出-
+--------------------------+ | if(Name='', 'Adam',Name) | +--------------------------+ | Chris | | Adam | | Robert | | Adam | | David | +--------------------------+ 5 rows in set (0.00 sec)