You are right, but what I tell my programmers: if you want high performant SQL-query you can make 2 things: 1. Think carefully about data and write generic S

You are right, but what I tell my programmers: if you want high performant SQL-query you can make 2 things: 1. Think carefully about data and write generic SQL without any DBMS specifics 2. Try to optimize everything with your DBMS specifics The latter - almost never works. Be it Oracle, MSSQL, DB2 or PostgreSQL. And even when it works - it's unacceptable. We had a query in Oracle that executed several hours. Our Oracle DBA found a way to tweak Oracle that shrinked it to 30 minutes. It was interesting, but impossible to use in practice - we could not guarantee that other queries will go fine with this server settings. (Our DBA was the first who was against using in production)