Wise Owl Training - SQL blogs (page 1 of 3)

Showing blogs 1-20 (out of 57)

In SSMS, how to add multiple aliases to tables using the ALT key

Posted by Andy Brown on 23 March 2016

It's only a small thing, but … this blog shows how you can click and drag with the ALT key held down, then type to apply a table alias to lots of tables simultaneously.

Tags:   SQL | Tables and columns    |    T-SQL | Other

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.

Tags:   SQL | CTEs, subqueries    |    T-SQL | Other

A short blog listing many ways to create aliases for columns in SQL

Posted by Andy Brown on 01 February 2016

It's not often that this owl learns new things about SQL when giving a course, but when I do, I like to share my new knowledge! This blog shows a new way to create aliases for columns in SQL.

Tags:   SQL | Selecting data    |    T-SQL | Other

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.

Tags:   SQL | Dynamic SQL    |    SQL | CTEs, subqueries    |    T-SQL | Other

Triggers in SQL Server

Posted by Andrew Gould on 27 November 2013

Triggers are special stored procedures that execute automatically in response to certain events in a database. This blog explains how to create three types of trigger in SQL Server: DML, DDL and Logon triggers.

Tags:   SQL | Triggers    |    T-SQL | SQL Tutorial

Transactions in SQL Server

Posted by Andrew Gould on 11 October 2013

This blog examines how to use Transactions in Microsoft SQL Server to allow you to control when data changes are committed to the database. You'll also discover how you can rollback transactions, effectively giving you the chance to undo changes to your data.

Tags:   SQL | Transactions    |    T-SQL | SQL Tutorial

How to use the LAG and LEAD functions included in SQL Server 2012

Posted by Andy Brown on 20 September 2013

SQL Server 2012 introduces new functions to find the previous or subsequent value for a row, without using a complicated self-join. This blog explains how to use LAG and LEAD, including partitioning row sets.

Tags:   SQL | Calculations    |    SQL Server 2012 | SQL 2012    |    T-SQL | New features

Wise Owl suggestions for new features for SQL Server Management Studio

Posted by Andy Brown on 09 September 2013

Writing SQL in Management Studio could, Wise Owl feel, be made a little easier: here are 10 practical suggestions for how!

Tags:   SQL | General    |    T-SQL | New features

How to debug T-SQL queries and stored procedures

Posted by Andy Brown on 06 June 2013

This blog gives the low-down on how to start and use the debugger included in SQL Server Management Studio 2008 R2 and SSMS 2012.

Tags:   SQL | Errors, debugging    |    T-SQL | SQL Tutorial

Deleting and Updating Records in SQL

Posted by Andrew Gould on 08 May 2013

This blog teaches you how to modify existing data in your database by either deleting records or updating them.

Tags:   SQL | Transactions    |    T-SQL | SQL Tutorial

How error messages work in SQL (including TRY, CATCH, RAISERROR and THROW)

Posted by Andy Brown on 03 May 2013

You can use BEGIN TRY to trap errors from SQL Server 2005 onwards, and also raise your own errors using RAISERROR or THROW - this blog explains all!

Tags:   SQL | Errors, debugging    |    T-SQL | SQL Tutorial

Using OUTER and CROSS APPLY joins to link to table-valued functions

Posted by Andy Brown on 03 May 2013

For the sake of completeness, this blog explains how to join to the results of table-valued functions (like a correlated subquery on steroids).

Tags:   SQL | Joins    |    SQL | Functions    |    T-SQL | SQL Tutorial

Output Parameters and Return Codes in SQL Server

Posted by Andrew Gould on 26 April 2013

This blog teaches you how to return values from your SQL stored procedures using two different techniques: return codes, and output parameters.

Tags:   SQL | Stored procedures    |    T-SQL | SQL Tutorial

Dynamic SQL

Posted by Andrew Gould on 22 April 2013

Dynamic SQL is a technique for building valid SQL statements from separate pieces of text. You can use this technique to create remarkably flexible and useful queries, as long as you're aware of the potential danger of SQL injection attacks.

Tags:   SQL | Dynamic SQL    |    T-SQL | SQL Tutorial

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.

Tags:   SQL | CTEs, subqueries    |    T-SQL | SQL Tutorial

Using Cursors in SQL Server

Posted by Andrew Gould on 26 March 2013

Cursors allow you to step through a set of data one record at a time. They’re not the quickest tool in SQL Server’s box, but they have their uses and this blog explains how they work.

Tags:   SQL | Cursors    |    T-SQL | SQL Tutorial

Loops in SQL

Posted by Andrew Gould on 18 February 2013

Many programming languages feature a variety of types of loop which allow your programs to repeat a set of instructions multiple times. In SQL there is only one type of loop, and this blog explains how it works!

Tags:   SQL | SQL programming    |    T-SQL | SQL Tutorial

Inline and multi-statement table-valued functions

Posted by Andy Brown on 08 February 2013

This blog shows you how to create table-valued functions in SQL (ie functions which return a table of data!).

Tags:   SQL | Programming tables    |    T-SQL | SQL Tutorial

How to create and use table variables in T-SQL

Posted by Andy Brown on 08 February 2013

Table variables allow you to hold rows of data in temporary storage, without any processing overhead. Read this blog to add this technique to your SQL armoury!

Tags:   SQL | Programming tables    |    T-SQL | SQL Tutorial

Exporting data from SQL Server Management Studio

Posted by Andrew Gould on 04 February 2013

While SQL Server Management Studio is a powerful tool for writing queries, it has absolutely no concessions towards making the results of those queries remotely presentable! This blog describes several techniques for getting the results of a query into another application so that you can format them to your heart’s content.

Tags:   SQL | General    |    T-SQL | SQL Tutorial
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