Note: the query optimizer considers using a functional index when the index expression is used in a relational expression or as an argument to one of the operator class functions.

注意：当索引表达式被用于关系表达式，或作为某个操作符类函数的参数时，查询优化器将考虑使用函数索引。

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Note: the query optimizer considers using a functional index when the index expression is used in a relational expression or as an argument to one of the operator class functions.

注意：当索引表达式被用于关系表达式，或作为某个操作符类函数的参数时，查询优化器将考虑使用函数索引。

youdao