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Use equality first.
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Use range operators only where equality does not apply.
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Avoid use of negatives in the form of !=
or NOT.
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Avoid LIKE pattern matching.
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Try to retrieve specific rows and in small numbers.
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Filter from large tables first to reduce rows joined.
Retrieve tables in order from the most highly filtered table downwards;
preferably the largest table has the most filtering applied.
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Tip 
The most highly filtered table is the table having the
smallest percentage of its rows retrieved, preferably the largest
table.
Use indexes wherever possible except for very small
tables.
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Let the Optimizer do its job.
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