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忽略MySQL中的空值并显示其余值

2024-04-24 23:42:03 347

使用ISNOTNULL查找非空值并显示它们。让我们首先创建一个表-

mysql> create table DemoTable1458
   -> (
   -> StudentName varchar(20),
   -> StudentScore int
   -> );

使用插入命令在表中插入一些记录-

mysql> insert into DemoTable1458 values('Chris Brown',56);
mysql> insert into DemoTable1458 values('David Miller',NULL);
mysql> insert into DemoTable1458 values('John Doe',78);
mysql> insert into DemoTable1458 values('Adam Smith',NULL);

使用select语句显示表中的所有记录-

mysql> select * from DemoTable1458;

这将产生以下输出-

+--------------+--------------+
| StudentName  | StudentScore |
+--------------+--------------+
| Chris Brown  |           56 |
| David Miller |         NULL |
| John Doe     |           78 |
| Adam Smith   |         NULL |
+--------------+--------------+
4 rows in set (0.00 sec)

这是忽略空值的查询-

mysql> select StudentName,StudentScore from DemoTable1458
   -> where StudentScore IS NOT NULL;

这将产生以下输出-

+-------------+--------------+
| StudentName | StudentScore |
+-------------+--------------+
| Chris Brown |           56 |
| John Doe    |           78 |
+-------------+--------------+
2 rows in set (0.00 sec)

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忽略MySQL中的空值并显示其余值

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