SQL Optimization Tips Part 1

• Use views and stored procedures instead of heavy-duty queries.
This can reduce network traffic, because your client will send to
server only stored procedure or view name (perhaps with some
parameters) instead of large heavy-duty queries text. This can be used
to facilitate permission management also, because you can restrict
user access to table columns they should not see.

• Try to use constraints instead of triggers, whenever possible.
Constraints are much more efficient than triggers and can boost
performance. So, you should use constraints instead of triggers,
whenever possible.

• Use table variables instead of temporary tables.
Table variables require less locking and logging resources than
temporary tables, so table variables should be used whenever possible.
The table variables are available in SQL Server 2000 only.

• Try to use UNION ALL statement instead of UNION, whenever possible.
The UNION ALL statement is much faster than UNION, because UNION ALL
statement does not look for duplicate rows, and UNION statement does
look for duplicate rows, whether or not they exist.

• Try to avoid using the DISTINCT clause, whenever possible.
Because using the DISTINCT clause will result in some performance
degradation, you should use this clause only when it is necessary.