MySQL Bugs: #7018: Group_Concat() Functionality Truncates Records

Bug #7018	Group_Concat() Functionality Truncates Records
Submitted:	5 Dec 2004 12:40	Modified:	6 Dec 2004 13:44
Reporter:	Christopher Robinson	Email Updates:
Status:	Not a Bug	Impact on me:	None
Category:	MySQL Server	Severity:	S2 (Serious)
Version:	4.1.7-nt	OS:	Windows (Windows XP)
Assigned to:		CPU Architecture:	Any

Description:
QUERY:
select main_string, GROUP_CONCAT(DISTINCT related_string ORDER BY related_string ASC SEPARATOR ';') from test_strings GROUP BY main_string;

Table DDL:
CREATE TABLE `test_strings` (
  `main_string` varchar(128) NOT NULL default '',
  `related_string` text
) ENGINE=MyISAM DEFAULT CHARSET=latin1

When running the query above we received truncated result sets. The related_string values are tuncated after a about a thousand characters. We verified and reloaded the data...the data are all in the table. We can select all data into an outfile - no problems. However, when GROUP_CONCAT() is applied the data are consistently truncated.

Thanks.

How to repeat:
We simply load the test strings into the table and re-run the query above.

Suggested fix:
Find out why it is truncating the records.

Hi,

What is the value of group_concat_max_len variable?
You can check it with:
mysql> select @@global.group_concat_max_len;
+-------------------------------+
| @@global.group_concat_max_len |
+-------------------------------+
|                          1024 |
+-------------------------------+
1 row in set (0.00 sec)

Thank you. This is obviously user error and not a bug. I am sorry to have bothered you.