VIEWs are an undervalued and underused feature in SQL. They basically consist of a query that has been given a name, and a parameter list, so can be used like an inline macro. Technically, you’re supposed to think of it as a virtual table.
The idea of an inline macro or inline function goes way back to the first versions of Fortran and later BASIC. Depending on the product, the syntax might look like this: FN DOUBLE (N) = (N + N). You had to give the name of the Macro, a simple optional parameter list, assignment operator, usually an