mysql返回表中某行或者多行的重复值操作教程
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2022-06-20 22:55:56
表tb_question
type
answer
a
1
a
1
b
2
b
3
c
4
1、作用于单列
select distinct [列名] from [表名]...
表tb_question
| type | answer |
| a | 1 |
| a | 1 |
| b | 2 |
| b | 3 |
| c | 4 |
1、作用于单列
select distinct [列名] from [表名];
例如：select distinct type from tb_question ;
运行之后：
| type |
| a |
| b |
| c |
2、作用于多列
select distinct [列名1],[列名2] from [表名];
例如：select distinct type,answer from tb_question ;
运行之后：
| type | answer |
| a | 1 |
| b | 2 |
| b | 3 |
| c | 4 |
注：distinct必须放在开头