Optimise/Tuning¶
Execution Plan¶
Make sure you have selected Query, Include Actual Execution Plan (or press the button on the tool bar).
When you run the query an extra tab will be displayed showing the Execution Plan.
Understanding the Execution Plan¶
Index Seek Vs. Index Scan (Table Scan) (PDF):
../../../misc/howto/microsoft/sql-server/sql-server-index-seek-vs-index-scan-table-scan.pdf
Copy of blog entry by Pinal Dave
Union¶
…change UNION
in the view to UNION ALL
. SQL does extra processing
when you do UNION
to ensure the rows returned are unique. As we know they
are unique we can use UNION ALL
.