Comparing Nullable Columns

Daniel Hutmacher shows an elegant way to compare multiple nullable columns on two tables:

Because we’ve added OR conditions into the mix, we’re forced to use the Nested Loop join, which loops over table B for every single row in A. That’s a lot of index scans and it comes with a hefty price tag.

Here’s an absolutely eye-watering beautiful pattern that I found on the Interwebs (though I forgot where) the other day.

This is an interesting use of INTERSECT.  Check it out.

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Trailing Spaces and String Comparisons

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T-SQL Bugs with Joins

Itzik Ben-Gan takes us through four bugs or oddities around joins: The order counts are now correct, but the total freight values are not. Can you spot the new bug? The new bug is more elusive because it manifests itself only when the same customer has at least one case where multiple orders happen to […]

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