Writing T-SQL - Common mistakes and assumptions compromising performance

This demo based performance session is for anyone who needs to write or analyse T-SQL code! I'll share some real-world code patterns and their performance issues that I've come across over time and possible ways to fix them. - Query is running slow? - Lets see how we can evaluate and improve it. - Using the right data types is not for you? Maybe this will make you change your mind. - Expecting partition elimination but it is not happening? - Maybe it is our fault! :) - User-defined functions, common table expression, table value parameters, and much more! In the end, you will understand the benefits of write T-SQL in the right way and that sometimes, using alternative techniques will outperform the most common approaches.