MySQL Bugs: #17832: group_concat seperator parameter doesn't accept variables

Bug #17832	group_concat seperator parameter doesn't accept variables
Submitted:	1 Mar 2006 18:41	Modified:	5 Mar 2006 9:04
Reporter:	Marques Johansson	Email Updates:
Status:	Verified	Impact on me:	None
Category:	MySQL Server: DML	Severity:	S4 (Feature request)
Version:		OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
The group_concat function has a seperator option described in the documents to take "expression" as it's parameter.  When passing a user variable (and others?) as "expression" an error is generated.

How to repeat:
mysql> select 2 as t,group_concat(2 separator ':');
t,group_concat(2 separator ':')
2, NULL
1 row in set (0.02 sec)

mysql> set @a=3; select 2 as t,group_concat(2 separator @a);
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '@a)' at line 1

I'm an evil liar and a wrottin spleler.  I was not reading from the official documents when I saw "expr" as the group_concat separator parameter.  The documents clearly state 'string'.  And so I am left asking, why not an expression?

I've changed the severity to 'Feature request'.

Thank you for a reasonable feature request.

Has this feature been added to 5.1?How can one over come this limitation or now, what a pity it only accepts literals!!

You can over this limitation by use this trick, for example :

GROUP_CONCAT(myfield,CHAR(11) SEPARATOR '') <= if you like a vertical tab separator

Bye !

Hy everyone!

and what about GROUP_CONCAT(column SEPARATOR CONCAT(':',':'))

I know that GROUP_CONCAT(column SEPARATOR '::') works fine but i'm actually trying to go deeper using the CONCAT function into the GROUP_CONCAT function. 

This exemple is not really what i want to do but it reveal the problem.

i'll try to express myself better :

As it is written in the documentation CONCAT function return a string and SEPARATOR is taking a string as argument.

So, why this way doesn't work?

Is this a bug or am I wrong somewhere?

I get error code : #1064 - You have an error in your SQL syntax;

So, why the problem is still not solved?

The fact that this hasn't been looked at in the last twenty years is very weird to me. Why the difference between CONCAT and GROUP_CONCAT ?
Being obligated to use a hardcoded expression for GROUP_CONCAT is immensely limitating its usage.