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在MySQL中基于空值在新列中显示自定义文本？

2024-05-17 11:11:04 354

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)

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在MySQL中基于空值在新列中显示自定义文本？

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