As you can see, the optimizer creates a virtual table to process the IN-list sub-query. 如您所见,优化器创建了一个虚拟表来处理IN列表子查询。
Getting a match on the column in position n+ 1 in the index key requires matching on the column in position n with an equal-type predicate or an in-list predicate. 在索引键中的位置n+1处获取一个匹配要求使用一个等于谓词或一个列表谓词匹配位置为n的列。
And if you want the like predicate applied before the in-list predicate, your coding order must reflect that. 如果您想相似谓词先于列表谓词应用,则您的编码顺序必须相应反映。
QB2 represents the IN-list sub-query while QB1 is the main sub-query. QB2代表IN列表子查询,而QB1代表主子查询。
Used for range, equality, or IN-list predicates 用于范围、等于或IN列表谓词
Likewise, the two range predicates will be applied in their coded order, and the in-list and like predicates were left in the order originally coded. 同样,那两个范围谓词也将以它们的编码顺序应用,列表和相似谓词遵循它们的原始编码顺序。