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Query optimization tips. Query optimizations tips:
- Always use a WHERE clause to restrict the number of returned queries.
- Only return the needed columns and rows that are needed by a query. Be wise of these while writing any query.
- Use views and stored procedures efficiently instead of complex queries.
- Avoid use of cursors wherever possible.
- Use SELECT rows FROM sysindexes WHERE id = OBJECT_ID('table_name') instead of SELECT COUNT(*) to know the number of rows returned.
- Use constraints instead of triggers when applicable.
- Use table variables efficiently.
- Avoid use of HAVING and DISTINCT clause.
- Use UINION ALL instead of UNION wherever possible.
- Do not use optimizer hints in queries.Query optimization tips. - Use indexes.
- Specify only the columns necessary while using select query.
- If join queries are used, indexes that match the join column must be used.
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