Press "Enter" to skip to content

Comparing Dates in a WHERE Clause

Erik Darling has been diving into issues with date comparison lately, including comparing date columns in the WHERE clause:

A common dilemma is when you have two date columns, and you need to judge the gap between them for something.

For instance, say you have a table of orders and you want to figure out how long on average it takes an ordered item to ship, or a shipped item to be delivered.

You’re not left with many good ways to write the query to take advantage of indexes.

Read on to see what Erik means, and one way you can speed it up a bit.