Database documentation

We would like to create a cheat sheet for database functions for our users. You must be familiar with general database and sql concepts. You will need to read the relevant documentation (all available on the web) for Oracle, DB2 and Postgres databases and provide a brief sumary of each one. Your deliverable will be a spreadsheet containing the following columns: 1) Function name 2) Function prototype (i.e., how it is called using sql syntax) 3) Type (string, numeric, date, etc.) 4) Brief description