This question came up in the recent SQL Server Performance Tuning Practical Workshop. During the workshop, I have answer questions of users during lunch break. One of the users had a very interesting scenario where he had to change one of their employee’s email address for technical reasons but before he changes that he needed to count in every single place where the email exists. I have simulated the same situation in this blog post and we will see how we can count a particular value across all the columns of the table.
SQL Server – Find Distinct Result Sets Using EXCEPT Operator
In my earlier post on “SQL SERVER – Remove Duplicate Rows Using UNION Operator”, I showed a different method of removing duplicate rows from the result set using a UNION operator. Here is another similar method using EXCEPT operator to find distinct results.
SQL SERVER – Performing IF…THEN In T-SQL With IIF Expression
Today, we are going to see one of the most underutilized features of SQL Server IIF. In SQL Server we can performance IF…THEN logic in T-SQL with IIF Expression but I hardly see it being used at most of the organization.
SQL SERVER – T-SQL Script to Check SQL Server Job History
Yesterday my long time customer from New Zealand asked me during our regular weekly meet of Comprehensive Database Performance Health Check if I know a T-SQL Script to Check SQL Server Job History.
SQL SERVER – How to Write Correlated Subquery?
This is a follow-up blog post to my earlier blog post written about SQL SERVER – Writing Your First Subquery From a Single Table. In the blog post, we discuss how to write a correlated subquery and why it is actually necessary. In a query, a correlated subquery is a subquery that uses values from the outer query. Subqueries are usually running once for each row processed for outer query and that is why they are often inefficient as well.
SQL SERVER – Writing Your First Subquery From a Single Table
My primary responsibility is to help different organizations with tuning their SQL Server Performance and here is the link to my most popular service SQL Server Performance Health Check. I often encounter complicated performance problems which are not easy to resolve, however, recently during the lunch break, I was asked by Junior developer a question about writing a subquery from a single table by a Junior DBA at the organizations.
SQL SERVER – Small Backup for Large Database
Recently, I had a very interesting experience with one of my customer while working with them on Comprehensive Database Performance Health Check. The issue was related to small backup for the large database and it was so much interesting I decided to share with all of you.