MySQL and GROUP_CONCAT() maximum length
Include this setting in xampp my.ini configuration file:
[mysqld]
group_concat_max_len = 1000000
Then restart xampp mysql
The correct parameter to set the maximum length is:
SET @@group_concat_max_len = value_numeric;
value_numeric
must be > 1024; by default the group_concat_max_len
value is 1024.
SET SESSION group_concat_max_len = 1000000;
is a temporary, session-scope, setting. It only applies to the current session You should use it like this.
SET SESSION group_concat_max_len = 1000000;
select group_concat(column) from table group by column
You can do this even in sharing hosting, but when you use an other session, you need to repeat the SET SESSION
command.