Question

I need to make an sql query which tries to update a row by primary key and if it doesn’t exist insert it. The solution needs to be universal for most databases (MySQL, H2, Postgres, Oracle, DB2, MSSQL, Hsql, Derby).

For code examples please consider a simple table consisting of two columns: id (Pr.Key) and txt

Answer 1

You want SQL’s MERGE statement, but it doesn’t work everywhere:

MERGE into thetable using (select theid from thetable)
when matched then update thetable thecolumn = thevalue where id = theid
when not matched then insert into thetable blablabla;

The other solution is to try and insert anyway, handle the error, detect whether it is a constraint violation and if so update instead.