Blogs from Wise Owl on CTEs, subqueries in SQL

Common Table Expressions are even better than I'd realised, as this blog shows

Posted by Andy Brown on 01 February 2016

CTEs (or Common Table Expressions) allow you to divide complicated queries up into two or more simple discrete tasks, as this blog explains.

Pivoting Data in SQL Server

Posted by Andrew Gould on 09 June 2014

Using the Pivot operator in SQL Server allows you to create basic pivot tables from your query results. This blog teaches you how to create simple, static pivots, crosstab-style tables and exciting, dynamic pivot tables.

Derived Tables in SQL

Posted by Andrew Gould on 08 April 2013

A derived table is a technique for creating a temporary set of records which can be used within another query in SQL. You can use derived tables to shorten long queries, or even just to break a complex process into logical steps.

SQL subqueries (including correlated subqueries)

Posted by Andrew Gould on 28 January 2013

If you’ve been writing SQL queries for a while you’re probably fairly confident with writing single SELECT statements to return a set of records. If you’re ready for a bit more of a challenge, this blog will teach you how to nest one SELECT statement inside another in order to create a subquery. If you’re thinking “that sounds simple enough” then you might want to read to the end of this series, where we’ll attempt to melt your brain by explaining correlated subqueries!

Free SQL training course | SQL tutorial

Posted by Andrew Gould on 13 February 2012

This article provides a comprehensive tutorial in Microsoft SQL Server, taking you from the basics of writing SELECT statements all the way through to creating complex stored procedures.

Common Table Expressions (CTEs) - SQL Training

Posted by Andy Brown on 20 October 2011

This blog gives training on writing CTEs in SQL, or Common Table Expressions to give them their full title. The blog also includes a section on creating recursive CTEs.