SQL - No Longer Set

SQL Gotcha: When an OUTER JOIN Accidentally Becomes an INNER JOIN

If you apply a WHERE filter directly to the OUTER JOIN side of a query you will effectively turn it into an INNER JOIN.

How do I check thee for NULL? Let me count the ways.

Did you get the error message, "Circular reference caused by alias 'MyField' in query definition's SELECT list"? Don't worry; it's an easy fix!

What's the difference between a RIGHT JOIN and a LEFT JOIN and why use one versus the other?

This improved version of my date-quoting convenience function eliminates a common source of date-handling ambiguity via the ISO date format.

This convenient function generates defensive SQL statements to help you avoid the subtle dangers of the BETWEEN statement when filtering dates.

Let's explore the GROUP BY syntax with an exercise in identifying duplicate records in a Person table.

If you're new to relational databases, the QBE window is the solution to--and cause of--many of your query problems.

Using the BETWEEN clause with date-time fields may lead to unexpected results. There's a safer alternative.