MySQL Bugs: #43605: ROW_COUNT() with UPDATE differentiate between 0 rows matched and 0 rows updated

Bug #43605	ROW_COUNT() with UPDATE differentiate between 0 rows matched and 0 rows updated
Submitted:	12 Mar 2009 16:54
Reporter:	Roger David Nay	Email Updates:
Status:	Verified	Impact on me:	None
Category:	MySQL Server: General	Severity:	S4 (Feature request)
Version:	Any	OS:	Any
Assigned to:		CPU Architecture:	Any

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Description:
After and UPDATE currently the ROW_COUNT() function does not differentiate between 0 rows matched for update and 0 rows updated, see manual (it has the same behaviour as mysql_affected_rows - http://dev.mysql.com/doc/refman/5.0/en/mysql-affected-rows.html). To differentiate between the two conditions an extra SELECT statement is required that can create performance issues if the table is heavily used.

How to repeat:
N/A

Suggested fix:
Add a return value of -2 that signifies 0 rows matched for update. Leave -1 for no rows updated/delete/inserted.