This may or may not be fast - it depends on how the query engine runs, and whether the optimizer can use an index when you apply a function on a column.

Probably premature optimization unless there are a lot of users, but PostgreSQL support indexes on expressions:
http://www.postgresql.org/docs/7.4/interactive/indexes-expressional.html.

As always, "explain" can be used to examine the optimizer's query plan.

In reply to Re^4: Backslash and Underscore problem with DBI and PostgreSQL. by ctilmes
in thread Backslash and Underscore problem with DBI and PostgreSQL. by Seumas

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