MariaDB比较运算符
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2023-03-14
MongoDB比较运算符用于测试等于或不等于，还有其它更高级的运算符。
在WHERE子句中使用比较运算符来确定要选择的记录。以下是可以在MariaDB中使用的比较运算符的列表：
语法及示例 -
| 编号 | 比较运算符 | 描述 | 示例 |
|---|---|---|---|
| 1 | = |
比较等于 | select * from students where id=100 |
| 2 | <=> |
比较等于(安全比较NULL值) |
select * from students where student_name<=>'Maxsu' |
| 3 | <> |
比较不等于 | select * from students where student_name<>'Maxsu' |
| 4 | != |
比较不等于 | select * from students where student_name!='Maxsu' |
| 5 | > |
比较大于 | select * from students where student_id>5 |
| 6 | >= |
比较大于或等于 | select * from students where student_id>=5 |
| 7 | < |
比较小于 | select * from students where student_id<5 |
| 8 | <= |
比较小于或等于 | select * from students where student_id<=5 |
| 9 | in ( ) |
匹配列表中的值 | select * from students where student_id IN(1,3,6) |
| 10 | not |
否定一个条件 | select * from students where student_id NOT IN(1,3,6) |
| 11 | between |
匹配在一个范围内(含) | select * from students where student_id between 1 AND 3) |
| 12 | is null |
判断是否为NULL值 |
select * from students where student_address IS NULL |
| 13 | is not null |
判断是否为非NULL值 |
select * from students where student_address IS NOT NULL |
| 14 | like |
与%和_模式匹配 |
select * from students where student_name LIKE 'Ma%' |
| 15 | exists |
如果子查询返回至少一行，则满足条件。 | — |