教您如何使用MySQL group_concat函数
MySQL group_concat函数是典型的字符串连接函数,下面就为您介绍MySQL group_concat的语法,希望对您学习MySQL group_concat函数有所帮助。
MySQL group_concat函数
完整的语法如下:
group_concat([DISTINCT] 要连接的字段 [Order BY ASC/DESC 排序字段] [Separator '分隔符'])
基本查询
- mysql> select * from aa;
- +------+------+
- | id| name |
- +------+------+
- |1 | 10|
- |1 | 20|
- |1 | 20|
- |2 | 20|
- |3 | 200 |
- |3 | 500 |
- +------+------+
- 6 rows in set (0.00 sec)
以id分组,把name字段的值打印在一行,逗号分隔(默认)
- mysql> select id,group_concat(name) from aa group by id;
- +------+--------------------+
- | id| group_concat(name) |
- +------+--------------------+
- |1 | 10,20,20|
- |2 | 20 |
- |3 | 200,500|
- +------+--------------------+
- 3 rows in set (0.00 sec)
以id分组,把name字段的值打印在一行,分号分隔
- mysql> select id,group_concat(name separator ';') from aa group by id;
- +------+----------------------------------+
- | id| group_concat(name separator ';') |
- +------+----------------------------------+
- |1 | 10;20;20 |
- |2 | 20|
- |3 | 200;500 |
- +------+----------------------------------+
- 3 rows in set (0.00 sec)
以id分组,把去冗余的name字段的值打印在一行,
逗号分隔
- mysql> select id,group_concat(distinct name) from aa group by id;
- +------+-----------------------------+
- | id| group_concat(distinct name) |
- +------+-----------------------------+
- |1 | 10,20|
- |2 | 20 |
- |3 | 200,500 |
- +------+-----------------------------+
- 3 rows in set (0.00 sec)
以id分组,把name字段的值打印在一行,逗号分隔,以name排倒序
- mysql> select id,group_concat(name order by name desc) from aa group by id;
- +------+---------------------------------------+
- | id| group_concat(name order by name desc) |
- +------+---------------------------------------+
- |1 | 20,20,10 |
- |2 | 20|
- |3 | 500,200|
- +------+---------------------------------------+
- 3 rows in set (0.00 sec)