MySQL Bugs: #58144: := operator missing from function/operation listing

Bug #58144	:= operator missing from function/operation listing
Submitted:	11 Nov 2010 16:19	Modified:	12 Nov 2010 19:37
Reporter:	Lig Isler-Turmelle	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Documentation	Severity:	S3 (Non-critical)
Version:	all	OS:	Any
Assigned to:	Jon Stephens	CPU Architecture:	Any

Description:
The := operator is missing from http://dev.mysql.com/doc/refman/5.1/en/func-op-summary-ref.html  So there is no way to find out about it unless you know where to look in the manual.

As noted on http://dev.mysql.com/doc/refman/5.1/en/user-variables.html

"For SET, either = or := can be used as the assignment operator.

You can also assign a value to a user variable in statements other than SET. In this case, the assignment operator must be := and not = because = is treated as a comparison operator in non-SET statements:

mysql> SET @t1=1, @t2=2, @t3:=4;
mysql> SELECT @t1, @t2, @t3, @t4 := @t1+@t2+@t3;
+------+------+------+--------------------+
| @t1  | @t2  | @t3  | @t4 := @t1+@t2+@t3 |
+------+------+------+--------------------+
|    1 |    2 |    4 |                  7 | 
+------+------+------+--------------------+
"

How to repeat:
N/A

Suggested fix:
Add to the documentation

Adopting this one following IRC discussion with Paul.

(Good catch, Lig!)

Issues in addition to those noted by the submitter:

1. The *assignment* form of = was not listed (it was listed as a *comparison* operator, but it can function as either one or the other, depending on the circumstances).

2. There were no descriptions of the = and := assignment operators in "Functions and Operators"

Resolution: 

1. The assignment operators = and := are now listed in the summary table.

2. A new section has been added to the "Functions and Operators" chapter with detailed descriptions of these; it will appear soon at http://dev.mysql.com/doc/refman/5.1/en/assignment-operators.html.