Use of indices for queries with comparisons based on a function

摘要

An index is used for a query that contains an original condition having a comparison based on a function. An implied condition is first identified and applied to values in a column having multiple rows. An index is used to identify rows having values meeting the implied condition. Finally, the query is executed over the index using the original condition. Flags may be used to identify how to handle exceptions during run time. A table may be used to provide bounds for multiple different functions.