Today, we will see another interesting topic where the index affects the delete statement. Let us start watching the video Indexing for Delete.
Remove Key Lookup – SQL in Sixty Seconds #194
Today, we are going to see one more trick from the book – Remove Key Lookup and improve the performance of queries.
One Default Row per Customer With a Filtered Unique Index
Two browser tabs, two default addresses. Here is how a filtered unique index keeps the rule in the database and how to switch defaults safely.
Splitting OR Conditions Into UNION ALL for Index Seeks
Test splitting OR conditions into disjoint UNION ALL branches, preserve NULL behavior and row identity, and compare actual index access.
TOP N Sort: Why a Small TOP Still Reads the Whole Table
Explain TOP N Sort, compare an indexed ordered access path, and align filter and sort keys before adding indexes for frequent requests.
SQL SERVER – Measure Index Performance
I measure index performance against the same workload before and after a change. A customer wanted to assess a new index.
A Unique Constraint That Allows Many NULLs
Allow many NULLs while enforcing unique non-NULL values with a filtered SQL Server index, required SET options, and tested queries.