First of all, each of these formats are very different, and you may need to lookup the exact format you need for your situation. With QIE 2.0.41 or later, you do have helpful guides within the Code Wizard and the Query Snippets menu for the database format date strings.
For additional documentation, see below.
Java Date Format
Oracle Database Date Format
SqlServer Database Date Format
Until recently, versions of SqlServer required an identifying number which formatted the text accordingly. You could not create a custom format.
(The above table is not complete.)
MySql Database Date Format