Bug #4258 Let EXIST work with INSERT
Submitted: 23 Jun 2004 11:14 Modified: 13 Dec 2005 16:41
Reporter: Kalle B Email Updates:
Status: Won't fix Impact on me:
None 
Category:MySQL Server Severity:S4 (Feature request)
Version: OS:Linux (FC2)
Assigned to: CPU Architecture:Any

[23 Jun 2004 11:14] Kalle B 
Description:
I want to insert a row only if it doesn't exist. I have tried something like this with variations but all fail.

How to repeat:
  INSERT INTO t1
  SET col = 'a'
  IF NOT EXISTS (
    SELECT * FROM t1
    WHERE col = 'a'
  )

or at least:

  INSERT INTO t1
  SET col = 'a'
  WHERE (
    SELECT COUNT(*) FROM t1
    WHERE col = 'a'
  ) = 0

Suggested fix:
I know that there is the REPLACE syntax, but I don't use unique keys and nevertheless REPLACE wouldn't be as versatile as this syntax.
Therefore I make it a feature request.
[13 Dec 2005 16:41] Valeriy Kravchuk 
Thank you for a feature request. Sorry, but I do not think any other way to deal with this kind of problems (besides REPLACE) is really needed. Please, declare primary keys for all your tables - it is a right way to use a relational database. And then just use REPLACE.