Function Indexes Not Used Within Correlated Subquery (Doc ID 2879803.1)

Last updated on JULY 14, 2022

Applies to:

MySQL Server - Version 8.0 and later
Information in this document applies to any platform.

MySQL 8.0 supports indexing a function. However, when that function is used within a dependent subquery, the index is not used.

For example, this table has both a function index, and also a generated virtual column with its own explicit index:

Here it has not rewritten the query to use the 'cat' index, but does not pick up the functional_index either.

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In this Document

Symptoms

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