MySQL Bugs: #41236: CONCAT inconsistently accepts string args without separating commas

Bug #41236	CONCAT inconsistently accepts string args without separating commas
Submitted:	4 Dec 2008 17:31	Modified:	4 Dec 2008 20:15
Reporter:	Peter Brawley (Basic Quality Contributor)	Email Updates:
Status:	Not a Bug	Impact on me:	None
Category:	MySQL Server	Severity:	S3 (Non-critical)
Version:	6.0.7	OS:	Any
Assigned to:		CPU Architecture:	Any
Tags:	qc

Description:
CONCAT() accepts literal strings without comma separation:

SELECT CONCAT('abc' 'def');
+---------------------+
| CONCAT('abc' 'def') |
+---------------------+
| abcdef              |
+---------------------+

... but not function args ...

SELECT CONCAT(RPAD('abc',5,' ') 'def');
ERROR 1583 (42000): Incorrect parameters in the call to native function 'CONCAT'

Non-literals require commas:

SELECT CONCAT(RPAD('abc',5,' '), 'def');
+----------------------------------+
| CONCAT(RPAD('abc',5,' '), 'def') |
+----------------------------------+
| abc  def                         |
+----------------------------------+

I suggest this inconsistency is undesirable at best.

How to repeat:
As above

Sorry, but this is not a bug. According to SQL standard, character string literal can be specified as:

'abc' 'def'

and implicit concatenation happens. So, in the first case CONCAT is applied just to one string literal argument. In the second case argument is string function RPAD(...) and then either ) or comma before the next argument is expected. Instead, we have a string literal. So, syntax is incorrect. In 5.0.x it was explicit:

C:\Program Files\MySQL\MySQL Server 5.0\bin>mysql -uroot -proot -P3308 test
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 22
Server version: 5.0.72-enterprise-gpl-nt MySQL Enterprise Server (GPL)

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql> SELECT CONCAT(RPAD('abc',5,' ') 'def');
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 ''def'
)' at line 1

5.1 and later tried to provide more clear and precise error message for this case.

A SQL anomaly, OK.

The 6.0.7 error message is ERROR 1583 (42000): Incorrect parameters in the call to native function 'CONCAT'