Efficient SQL

Whether you refer to them as queries, reports, stored procedures, or views, they’re all SQL queries. They’re at the heart of all the data access and modifications made to a database.

For SQL queries to execute effectively and efficiently, they require a combination of several things:

  1. They must be written efficiently in a way that makes effective and efficient use of shared and sometimes scarce server and database resources.
  2. They must have supporting indexes, properly implemented according to specific rules, that allow them to execute efficiently.
  3. They must execute with concurrency, not locking out other queries attempting to access data from the same location in a database.
  4. They must have supportive database infrastructure, configured according to best practices.
  5. They must have supportive disk I/O subsystems, configured according to best practices.
  6. They must have supportive server hardware that can support the demands placed on the server.

Even the best written SQL queries cannot execute effectively and efficiently if best practices are not implemented to create a supportive infrastructure and server environment.

Unlike software languages which emphasize a “for each” paradigm, the SQL language works with datasets using a “for all” paradigm. Technically speaking, SQL is not a particularly elegant or efficient language. It has hundreds of syntax rules and many variations on basic instructions. It takes time and experience to master it.

Writing efficient SQL is both a skill and an art, mastered only with practice and persistence. There are many ways to write SQL statements to accomplish the same objectives. The skill and art of it is knowing how to write a SQL query efficiently.

If you need help with performance tuning your SQL Server,  contact me to schedule a free consultation.