Automatic Sample Sizes for Statistics Updates

I mentioned in my previous post about manually updating statistics that you can specify whether they’re updated using a full...

How to be a bad interviewer

In the monthly SQL blogging party that is T-SQL Tuesday (brainchild of Adam Machanic), Kendra Little has invited us this...

Manually updating Statistics

Even though SQL Server automatically updates statistics in the background for you, you may find there are times when you...

Statistics and the Ascending Key Problem

I’ve mentioned previously how not having up to date statistics can cause problems in query performance. This post looks at...

SQL Server Agent and Daylight Saving time

There was a bit of chat today on the SQL Community slack about UTC and Daylight Saving Time. It reminded...

SQL Puzzle 2: Eight Queens

This puzzle was first proposed in 1848 by a composer of chess puzzles called Max Bezzel and has since spawned...

Think twice before using table variables

T-SQL Tuesday

For T-SQL Tuesday this month Raul Gonzalez has asked us all to blog about lessons learnt the hard way:
http://www.sqldoubleg.com/2017/07/03/tsql2sday-92-lessons-learned-the-hard-way/
My...

When do Distribution Statistics Get Updated?

Statistics objects are important to us for allowing SQL to make good estimates of the row-counts involved in different parts...

Row-count Estimates when there are no Statistics

I was discussing Cardinality Estimation with a colleague recently and the question came up, what cardinality does SQL Server use...

Statistics and Cardinality Estimation

Cardinality
This is a term originally from Mathematics, generally defined as “The number of objects in a given set or grouping”....