小编Viv*_*ekh的帖子

我必须选择小于给定 id 且大于给定 id 的 2 个值。我已经尝试过这个查询，但有没有更好的方法来做到这一点

小提琴Sql

Begin 

declare @rootValue int
declare @repID int

set @repID = 2
set @rootValue = (select Id from tblLookups where Id = @repID)

declare @rootMinusTwo int
declare @rootPlusTwo int

set @rootMinusTwo = (select count(*) from tblLookups where Id < @rootValue)
set @rootPlusTwo = (select count(*) from tblLookups where Id > @rootValue)

if @rootMinusTwo >= 2 and @rootPlusTwo >= 2
Begin
    select *  
    from tblLookups 
    where Id between @rootValue - 2 and @rootValue …

我有一个包含数百万条记录的 SQL 数据库，当我查询数据时

select * from ActCosts where ScenarioID= 456

这些表有 1,323,718 行，它给了我 50,000 多行，这令人惊讶地花费了 3 多分钟。所以我现在正在考虑如何改进这个性能。我发现一种方法是在“SomeID”列上创建索引。我已经创建了这个索引，但查询需要相同的时间

执行计划

索引脚本

CREATE NONCLUSTERED INDEX [IX_ActCost_ScenarioID] ON [dbo].[ActCost] 
(
    [ScenarioID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON)
GO


ALTER TABLE [dbo].[ActCost] ADD  CONSTRAINT [PK_ActCost] PRIMARY KEY CLUSTERED 
(
    [ActCostID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, ONLINE …