mysql pdo php postgresql sqlite

Syntax differences between mysql, sqlite and pgsql

I’m creating a tiny activerecord library using PDO and I’m planning to support MySQL, Sqlite and PgSQL.

My question is how I can be sure that the query string works with all adapters? There will mostly be CRUD statements with some joins etc. Is there a standard I can follow that works for all of these?

/ Tobias

EDIT: Thanks for all your answers but my question was more about the SQL ‘syntax‘ differences between them.