A-level Computing/AQA/Problem Solving, Programming, Operating Systems, Databases and Networking/Databases/SQL





Structured Query Language (SQL) is used to perform function on a database. There are four main functions that you should be familiar with: SELECT, INSERT, UPDATE, DELETE

To help us understand how these things work we are going to use a test data set. Databases are used in all areas of the computer industry, but for the moment we are going to use a dataset that keeps track of crooks in England, noting, names, gender, date of birth, towns and numbers of scars. Take a look at the crooks data table below:

To select all the items from this table we can use: This would display all the results. But what if we just want to display the names and number of scars of the female crooks? The result of this query would be:

You can practice your SQL skills using Access, MySQL (as part of XAMPP), MSSQL, SQLite etc. If you don't have this software easily available you might want to take a look at the SQLZoo site, which allows you to hone your skills in an online environment where you don't have to worry about accidentally deleting all your records! For the exam and probably for your projects you need to be very good at SQL, so get practicing.

http://filestore.aqa.org.uk/subjects/AQA-2510-W-TRB-COMP3QDUSQL.PDF