Question

它只是我在SQL中的启动，我有4.5 GB的数据库，我试图从特定日期选择记录并执行25秒。有没有办法让它更快？

我的查询：

select a.*,b.ModelName
from Validation a
left Join ModelMaster b
    on SUBSTRING(a.STB,11,2) = b.ProductCode and
    Convert(int,substring(a.STB,9,2)) = b.BrandCode
Where STB in (Select STB From Scan_Data_For_Century) and
    a.date between '2015-01-14' and '2015-01-14'

Answer 1

您可以尝试这样的查询：

SELECT  a.*,
        b.ModelName
FROM Scan_Data_For_Century sd
INNER JOIN Validation a
    ON a.STB = sd.STB AND a.date between '2015-01-14' and '2015-01-14'
LEFT JOIN ModelMaster b
    ON SUBSTRING(a.STB,11,2) = b.ProductCode AND Convert(int,substring(a.STB,9,2)) = b.BrandCode

我知道，那一定是评论。请尝试查询。如果它不会帮助我将删除我的答案。

Answer 2

试试这个：

;with cte as (
select 
    *, 
    ProductCode = SUBSTRING( STB, 11, 2 ), 
    BrandCode = Convert( int, substring( STB, 9, 2 ) ) 
from Validation
)
select
    a.*,
    c.ModelName
from 
    cte a
    inner join Scan_Data_For_Century b on ( b.STB = a.STB )
    left Join ModelMaster c on ( c.ProductCode = b.ProductCode ) and ( c.BrandCode = b.BrandCode )
Where     
    ( a.date = '2015-01-14' )

还索引：

Validation.STB
Validation.Date
Scan_Data_For_Century.STB
ModelMaster.ProductCode
ModelMaster.BrandCode

可能有帮助

如何缩短执行时间

2 个答案: