WorkFine | 判断为空和不为空is null和is not null用法示例

mysql> select * from tmp ;
+------+----------+
| id   | name     |
+------+----------+
|    2 | lisi     |
|    1 | zhangsan |
|    3 | NULL     |
+------+----------+
3 rows in set (0.00 sec)

mysql> select * from tmp where name is null;
+------+------+
| id   | name |
+------+------+
|    3 | NULL |
+------+------+
1 row in set (0.00 sec)

mysql> select * from tmp where name is not null;
+------+----------+
| id   | name     |
+------+----------+
|    2 | lisi     |
|    1 | zhangsan |
+------+----------+
2 rows in set (0.00 sec)

mysql> 
————————————————
查询某个字段的值是否为NULL，很简单但要知道，这个面试也考的多。
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原文链接：https://blog.csdn.net/ma2595162349/article/details/80355903