{"attachments":[],"attr":{},"bold":false,"channelId":445,"checked":true,"collectsCount":0,"commentsCount":0,"commentsDay":0,"contentCount":{"collects":0,"collectsDay":0,"collectsMonth":0,"collectsWeek":0,"comments":0,"commentsDay":0,"commentsMonth":0,"commentsWeek":0,"downloads":0,"downloadsDay":0,"downloadsMonth":0,"downloadsWeek":0,"downs":0,"id":101484,"likes":0,"likesDay":0,"likesMonth":0,"likesWeek":0,"ups":0,"upsDay":0,"upsMonth":0,"upsWeek":0,"views":6237,"viewsDay":0,"viewsMonth":5,"viewsWeek":1},"contentExt":{"bold":false,"description":"MySQL提供的group_concat函数可以拼接某个字段值成字符串,如 select group_concat(user_name) from sys_user,默认的分隔符是 逗号,即\",\" ,如果需要自定义分隔符可以使用 SEPARATOR","editDate":1574734332000,"id":101484,"releaseDate":1574734332000,"stitle":"GROUP_CONCAT()函数最大长度限制","title":"GROUP_CONCAT()函数最大长度限制","tplMobileContent":""},"contentImgWhole":"GROUP_CONCAT()函数最大长度限制","contentTxt":{"id":101484,"txt":"
MySQL提供的group_concat函数可以拼接某个字段值成字符串,如 select group_concat(user_name) from sys_user,默认的分隔符是 逗号,即"," ,如果需要自定义分隔符可以使用 SEPARATOR
如:select group_concat(user_name SEPARATOR '_') from sys_user
但是如果 user_name 拼接的字符串的长度字节超过1024 则会被截断。
通过命令 "show variables like 'group_concat_max_len' " 来查看group_concat 默认的长度:
操作方法:
(1)在MySQL配置文件中加入:
group_concat_max_len = 102400
(2)更简单的操作方法,执行SQL语句:
SET GLOBAL group_concat_max_len = 102400;\r\nSET SESSION group_concat_max_len = 102400;
注意:该方法缺点是重启服务后设置失效
MySQL提供的group_concat函数可以拼接某个字段值成字符串,如 select group_concat(user_name) from sys_user,默认的分隔符是 逗号,即"," ,如果需要自定义分隔符可以使用 SEPARATOR
如:select group_concat(user_name SEPARATOR '_') from sys_user
但是如果 user_name 拼接的字符串的长度字节超过1024 则会被截断。
通过命令 "show variables like 'group_concat_max_len' " 来查看group_concat 默认的长度:
操作方法:
(1)在MySQL配置文件中加入:
group_concat_max_len = 102400
(2)更简单的操作方法,执行SQL语句:
SET GLOBAL group_concat_max_len = 102400;\r\nSET SESSION group_concat_max_len = 102400;
注意:该方法缺点是重启服务后设置失效