CODEWITHSUNDEEP
mysqlsql-update
Jason
Jason

Reputation: 15335

SQL to update a table only if that table exists in the database

I have a mySQL database that might have a table named jason. A separate instance of the database may not have the jason table (it would have other tables in common)

I'd like to run a simple update against both databases but the update is for the jason table.

I know I can do something like

DROP TABLE IF EXISTS `jason`;

Is it possible to run an Update something like:

IF EXISTS `jason` UPDATE `jason` SET...

I can't seem to get anything to work.

Upvotes: 6

Views: 7223

Answers (4)

Erik Elkins
Erik Elkins

Reputation: 629

It won't fail but if you insist, you can do a work around:

IF EXISTS (SELECT * FROM Table1)
   UPDATE Table1 SET (...) WHERE Column1='SomeValue'
ELSE
   INSERT INTO Table1 VALUES (...)

Upvotes: -2

neouser99
neouser99

Reputation: 1827

You could also refer to these mysql docs. All the schema information is in a database, so essentially you can do any queries in the same fashion. Examples towards the bottom.

Upvotes: 0

Andomar
Andomar

Reputation: 238116

If you name a non-existant table, the update statement will fail to compile. You'll need to generate dynamic SQL and execute it only when the table exists.

Upvotes: 0

Null303
Null303

Reputation: 1042

Just run the update statement, if the table didn't exist, it will fail and cause no damage.

Upvotes: 2

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