If application works with a database, query execution time should be taken into consideration.
But I decided to share my own experience in the field with the focus on SQL Server query optimization tips.
Depending on a specific case, this task can have varying starting conditions:
You already know what query runs slowly;
You only know that your entire system has generally poor performance that requires some tuning.
You can run SQL Server Profiler from SQL Server Management Studio: go to Tools > SQL Server Profiler
0