averyanov@stripped wrote:
> i've got a strange problem with concat() function
>
> i have the following data structure:
>
> CREATE TABLE table1 (
> field1 int(11) NOT NULL auto_increment,
> PRIMARY KEY (field1)
> ) ENGINE=MyISAM DEFAULT CHARSET=cp1251 AUTO_INCREMENT=3;
>
> CREATE TABLE table2 (
> field2 varchar(255) NOT NULL default ''
> ) ENGINE=InnoDB DEFAULT CHARSET=cp1251;
>
> INSERT INTO table1 VALUES (1);
> INSERT INTO table1 VALUES (2);
> INSERT INTO table2 VALUES ('test');
>
> When i try to execute the following query
> (the query is meaningless -- it is generated just for debug purpose.
> the original query where the problem occured is too long and
> complicated)
This is an important point. Do you get the reported error for the simplified
query below? If not, it is useless. To find the problem, we must have a
query that produces the problem.
> SELECT
> COUNT(DISTINCT field1) as value1,
> CONCAT(field2, '-') as value2
> FROM
> table1,
> table2
> GROUP
> BY value2
With 4.1.11 on Mac OS X 10.3.9, I get
+--------+--------+
| value1 | value2 |
+--------+--------+
| 2 | test- |
+--------+--------+
1 row in set (0.09 sec)
> i get this error:
>
> ERROR 2006 (HY000): MySQL server has gone away
> No connection. Trying to reconnect...
> Connection id: 6
> Current database: test
> ERROR 2013 (HY000): Lost connection to MySQL server during query
Does the mysql server actually crash, or are you just losing the connection
from your client? Have you checked the error log? Have you checked the
manual <http://dev.mysql.com/doc/mysql/en/gone-away.html>?
> but if i change my query to this one everything is fine
> SELECT
> COUNT(DISTINCT field1) as value1,
> CONCAT(field2, '') as value2
> FROM
> table1,
> table2
> GROUP
> BY value2
>
> (here CONCAT(field2, '-') is replaced with CONCAT(field2, '') )
>
> does anyone know what the matter is?
Does the simple query
SELECT CONCAT('test', '-');
work or produce the same error?
> ps
> my mysql version is
> mysql Ver 14.7 Distrib 4.1.12, for unknown-freebsd4.6 (i386) using EditLine
> wrapper
> and my system is FreeBSD 4.6
I've not used "EditLine wrapper" with mysql. Is there any chance it is doing
something with '-'?
Michael
