Within computing, author O'Connell defines '''join selection factor''' as "[t]''he percentage (or fraction) of records in one file that will be joined with records of another file''".<ref>O'Connell, S. (2005) ''Advanced Databases Course Notes'', Southampton, University of Southampton, section 5.10</ref> This can be calculated when two database tables are to be joined. It is primarily concerned with query optimization.
== References == {{reflist}}
Category:Database algorithms
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