EXPLAIN EXTENDED

How to create fast database queries

Archive for October, 2013

5 Claims About SQL, Explained

with 2 comments

1. Is SQL is a declarative language?

First of all, let's define the terms.

A declarative language describes the result, not the process to achieve it. In a declarative language you tell "what do I need".

A procedural language describes control flow: exact steps the machine needs to perform in order to achieve this result. In a procedural language you tell "what do you do".

SQL, as it was originally designed, is a declarative language.

2980020699_0dfbe889f7_o

For instance you need to know how many customers above 40 live in each city. You issue a query like:

Read the rest of this entry on tech.pro ยป

Written by Quassnoi

October 28th, 2013 at 11:00 pm

Posted in Miscellaneous