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  • MYSQL 分组合并函数

    From: http://blog.csdn.net/wwwyuanliang10000/article/details/27536175

    MySQL中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)

     

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  • 原文地址:https://www.cnblogs.com/joeblackzqq/p/5367751.html
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