In the previous posts, we have learned why Scalar Functions (UDFs) are bad for parallelism and performance and what the options are for their removal.
The only remaining question is where to start. You’ve probably guessed there isn’t one true way to approach this. So instead, I offer several strategies that you can combine.
Plus Tom has an offer for you at the bottom of the post: conversion from Scalar UDFs to Inline Table-Valued Functions, which tend to perform much better.