我正在尝试调整一些存储过程并对索引有疑问。我使用了调优顾问,他们推荐了两个索引,都用于同一个表。问题是一个索引用于一列,另一个索引用于多列,其中它包含与第一列相同的列。我的问题是为什么和有什么区别?
CREATE NONCLUSTERED INDEX [_dta_index_Table1_5_2079723603__K23_K17_K13_K12_K2_K10_K22_K14_K19_K20_K9_K11_5_6_7_15_18]
ON [dbo].[Table1] (
[EfctvEndDate] ASC,
[StuLangCodeKey] ASC,
[StuBirCntryCodeKey] ASC,
[StuBirStOrProvncCodeKey] ASC,
[StuKey] ASC,
[GndrCodeKey] ASC,
[EfctvStartDate] ASC,
[StuHspncEnctyIndctr] ASC,
[StuEnctyMsngIndctr] ASC,
[StuRaceMsngIndctr] ASC,
[StuBirDate] ASC,
[StuBirCityName] ASC
) INCLUDE (
[StuFstNameLgl],
[StuLastOrSrnmLgl],
[StuMdlNameLgl],
[StuIneligSnorImgrntIndctr],
[StuExpctdGrdtngClYear]
) WITH (SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF)
ON [PRIMARY] go
CREATE NONCLUSTERED INDEX [_dta_index_Table1_5_2079723603__K23]
ON [dbo].[Table1] (
[EfctvEndDate] ASC
)WITH (SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF)
ON [PRIMARY]