The reason and solution of group_concat error in MySQL statistic function

Today, the following SQL statement was executed, and the result was an error.

CREATE table Car_user_content Select Addr_id,comm_userid,group_concat (comm_content) as content from (SELECT * from Forum_ Comment Union SELECT * from Forum_comment1) as Te GROUP by Addr_id,comm_userid;

Joint function Group_concat is used here, but when used, the result reported the following error.

ERROR 1260 (HY000): Row ' is cut by Group_concat ()

Reason

Group_concat truncate the result, Group_concat has a maximum length limit, and the maximum length is truncated. You can view its memory limits with the following command.

SELECT @ @global. Group_concat_max_len;

Solve

Enlarge the maximum memory limit using the following command.

SET GLOBAL group_concat_max_len=102400;

url:http://blog.csdn.net/qy20115549/article/details/53939021