sql中like与%%的用法
mysql> select * from a;
+-------+----------+
| id | name |
+-------+----------+
| 1000 | zhangsan |
| 2000 | lisi |
| 3000 | NULL |
+-------+----------+
3 rows in set
mysql> mysql> select * from a
-> where name like '%%';
+-------+----------+
| id | name |
+-------+----------+
| 1000 | zhangsan |
| 2000 | lisi |
+-------+----------+
2 rows in set
mysql> 注意上例:
like '%%' 表示查询列有不为null的全部值
mysql> select * from b;
+-------+--------+
| id | goods |
+-------+--------+
| 1000 | TV |
| 2000 | Camera |
| 3000 | cup |
| 4000 | box |
+-------+--------+
4 rows in set
mysql> select * from b
-> where goods like '%%';
+-------+--------+
| id | goods |
+-------+--------+
| 1000 | TV |
| 2000 | Camera |
| 3000 | cup |
| 4000 | box |
+-------+--------+
4 rows in set
mysql>
本文详细介绍了SQL中LIKE操作符与通配符%%的使用方法,通过具体实例展示了如何利用LIKE进行模糊查询,特别关注NULL值处理及%%通配符在不同情况下的表现。
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