Given a partitioned table and a simple SELECT query that compares the partitioning column to a single literal value, why does SQL Server read all the partitions when it seems obvious that only one partition needs to be examined? Sample Data The following script creates a table, partitioned on the char(3) column ‘Div’, and populates it with ...

Most people know that a LIKE predicate with only a trailing wildcard can usually use an index seek: SELECT p.Name FROM Production.Product AS p WHERE p.Name LIKE N'D%'; As the execution plan shows, SQL Server determines a covering range (which depends on the collation), seeks the ...

You probably already know that it’s important to be aware of data types when writing queries, and that implicit conversions between types can lead to poor query performance.  Some people have gone so far as to write scripts to search the plan cache for CONVERT_IMPLICIT elements, and others routinely inspect plans for that type of thing when ...