Find overlapping indexes, compare ordered keys and INCLUDE lists, merge coverage carefully, and review usage before removing either index.
Does Column Order in CREATE TABLE Change How Rows Are Stored?
Someone wants to reorder columns to shrink rows. I measured it on SQL Server 2025, and the answer is mostly no, with one small exception worth knowing.
SQL SERVER – Avoid Using Function in WHERE Clause – Scan to Seek
Does a function in WHERE clause really hurt performance? Using AdventureWorks and STATISTICS IO, I show what happens and how to turn a scan into a seek.
SQL SERVER – An Interesting Case of Redundant Indexes – Index on Col1 and Included Columns Col2 and Col3 – Part 5
Part 5 of my redundant indexes series looks at an index on Col1 with included columns Col2 and Col3, and how it compares with the earlier cases.
SQL SERVER – Primary Key and NonClustered Index in Simple Words
In 2006 I wrote how Primary Key and Unique Key differ. Now I fill the gap and explain primary key and nonclustered index in simple words.
SQL SERVER – An Interesting Case of Redundant Indexes – Index on Col1, Col2 and Index on Col1, Col2, Col3 – Part 4
A recap of this case of redundant indexes, from Jon and Mike’s basics to the demos where redundant indexes are useful with small and large result sets.
SQL SERVER – An Interesting Case of Redundant Indexes – Index on Col1, Col2 and Index on Col1, Col2, Col3 Part 3
Index on Col1, Col2 and index on Col1, Col2, Col3 Part 3: Jon and Mike ask if it is always best practice to drop redundant indexes. Here is a special case.