group_concat字符长度限制
使用方法
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)
可以得到分组中的值连接后的结果,mysql默认长度1024,如果字符太长会被截掉,想要完整数据可以在my.ini内增加
group_concat_max_len = 9999999999 改为自己需要的长度即可。