MySQL “good” way to insert a row if not found, or update it if it is found

Question

Very often, I want to run a query on one of my users where I want a row stored and associated with that user, in a 1-to-1 relationship. So let\'s say (this is just an arbit

Answer 1

In Oracle you have Merge.

No idea on MySql, but the term might give you something else to search.

Answer 2

This is called an UPSERT (UPdate or inSERT). There are a number of SO questions about it you can search for. See Wikipedia

EDIT: MySQL 4.1+ supports INSATE (INSert or updATE), which should get you the same thing, as long as you have a primary key. MySQL Manual

Answer 3

an example of how I have used ON DUPLICATE KEY UPDATE: INSERT INTO registry (name, value) VALUES ('" . $key . "', '" . $val . "') ON DUPLICATE KEY UPDATE value= '" . $val . "'"

Answer 4

From my other Stack Overflow answer:

If you want to do this in a single statement, I would recommend using the INSERT ... ON DUPLICATE KEY UPDATE syntax, as follows:

INSERT INTO table (id, someothervalue) VALUES (1, 'hi mom')
  ON DUPLICATE KEY UPDATE someothervalue = 'hi mom';

The initial INSERT statement will execute if there is no existing record with the specified key value (either primary key or unique). If a record already exists, the following UPDATE statement (someothervalue = 3) is executed.

This is supported in all versions of MySQL. For more info, see the MySQL Reference Manual page for INSERT ... ON DUPLICATE KEY UPDATE

Answer 5

I think it's easier to switch it around. Try to insert, then update.

MySQL specifically has a clause 'ON DUPLICATE KEY'

INSERT INTO cars (fields) VALUES (values) ON DUPLICATE KEY UPDATE ...

This of course requires you to have proper unique keys setup.

Answer 6

You can use "REPLACE INTO" or "INSERT… ON DUPLICATE KEY UPDATE". I believe the second is what you want, but there are situations where REPLACE INTO is convenient.