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.

Related Posts

Shuffling Data And Zipping Results In T-SQL

Phil Factor continues his series on pseudonymization: The problems come with uncommon values. If you are pseudonymizing a medical database that is required for research purposes on people with potentially embarrassing diseases, and it appears on the dark web, anyone with a rare or unusual surname or first-name comes up on the list, so the […]

Read More

Last Observation Carried Forward In T-SQL

Pawan Khowal shows one example of implementing Last Observation Carried Forward in T-SQL: A very close friend given this to me. In this puzzle you have to fill the price of SKU & Color Id for missing months. Note that SKU & Color Id should be considered as a business unit. So you have to […]

Read More

Categories

July 2016
MTWTFSS
« Jun Aug »
 123
45678910
11121314151617
18192021222324
25262728293031