在MySQL中基于空值在新列中显示自定义文本？
让我们首先创建一个表-
mysql> create table DemoTable1953 ( StudentName varchar(20) );
使用插入命令在表中插入一些记录-
mysql> insert into DemoTable1953 values('Chris');
mysql> insert into DemoTable1953 values(NULL);
mysql> insert into DemoTable1953 values('David');
mysql> insert into DemoTable1953 values(NULL);使用select语句显示表中的所有记录-
mysql> select * from DemoTable1953;
这将产生以下输出-
+-------------+ | StudentName | +-------------+ | Chris | | NULL | | David | | NULL | +-------------+ 4 rows in set (0.00 sec)
以下是根据空值在新列中显示自定义文本的查询-
mysql> select StudentName,IF(StudentName IS NULL,'Student Name Is Not Found','Student Name Found') as Name from DemoTable1953;
这将产生以下输出-
+-------------+---------------------------+ | StudentName | Name | +-------------+---------------------------+ | Chris | Student Name Found | | NULL | Student Name Is Not Found | | David | Student Name Found | | NULL | Student Name Is Not Found | +-------------+---------------------------+ 4 rows in set (0.00 sec)