Are sql tuning ways same for different DB engine？ I used Oracle for the half past year and learned some tricks of sql tuning,but now our DB is moving to greenplum and the project manager suggest us to change some of the codes that writted in Oracle sql for their efficiency.

I am curious that Are sql tuning ways same for different DB engine,like oracle,postgresql,mysql and so on？if yes or not,why?Any suggestion are welcomed!
The "tricks" are to convince the DBMS to behave the way you want it to. These are large, complex pieces of software. No two behave exactly the same. So tricks that affect one may or may not work with another.

Good practice, such as only retrieving columns that a actually needed, is applicable everywhere.