使用 SQL Server 2012 提高查询的性能？

Question

我有一个包含 13,0000 条记录的表，但没有索引，我编写了一个包含 4 个 LEFT OUTER JOIN 的查询。

查询运行良好，没有任何问题。我唯一关心的是性能，给出结果需要 5-10 分钟。所以我的问题是如何提高查询的性能？我的第二个问题是我需要添加索引吗？如果是，我应该添加哪个索引，集群还是非集群？

我的查询是：

SELECT Z.* FROM
(SELECT
YTD.Specialisation,
YTD.SpecialisationCode,
ROUND(COALESCE(Today.Revenue_Today,0),0)Revenue_Today,
ROUND(COALESCE(MTD.Revenue_MTD,0),0)Revenue_MTD,
ROUND(COALESCE(YTD.Revenue_YTD,0),0)Revenue_YTD,
ROUND(COALESCE(DTD.Revenue_DTD,0),0)Revenue_DTD,

ROUND(COALESCE(Today.Amount1_Today,0),0)Amount1_Today,
ROUND(COALESCE(MTD.Amount1_MTD,0),0)Amount1_MTD,
ROUND(COALESCE(YTD.Amount1_YTD,0),0)Amount1_YTD,
ROUND(COALESCE(DTD.Amount1_DTD,0),0)Amount1_DTD,

ROUND(COALESCE(Today.Amount2_Today,0),0)Amount2_Today,
ROUND(COALESCE(MTD.Amount2_MTD,0),0)Amount2_MTD,
ROUND(COALESCE(YTD.Amount2_YTD,0),0)Amount2_YTD,
ROUND(COALESCE(DTD.Amount2_DTD,0),0)Amount2_DTD,

ROUND(COALESCE(Today.Amount3_Today,0),0)Amount3_Today,
ROUND(COALESCE(MTD.Amount3_MTD,0),0)Amount3_MTD,
ROUND(COALESCE(YTD.Amount3_YTD,0),0)Amount3_YTD,
ROUND(COALESCE(DTD.Amount3_DTD,0),0)Amount3_DTD,

ROUND(COALESCE(Today.Amount4_Today,0),0)Amount4_Today,
ROUND(COALESCE(MTD.Amount4_MTD,0),0)Amount4_MTD,
ROUND(COALESCE(YTD.Amount4_YTD,0),0)Amount4_YTD,
ROUND(COALESCE(DTD.Amount4_DTD,0),0)Amount4_DTD,

ROUND(COALESCE(Today.Amount5_Today,0),0)Amount5_Today,
ROUND(COALESCE(MTD.Amount5_MTD,0),0)Amount5_MTD,
ROUND(COALESCE(YTD.Amount5_YTD,0),0)Amount5_YTD,
ROUND(COALESCE(DTD.Amount5_DTD,0),0)Amount5_DTD


FROM
(select
a.SpecialisationCode,
a.Specialisation,
SUM(a.DoctorFee)Revenue_YTD,
SUM(a.Amount1)Amount1_YTD,
SUM(a.Amount2)Amount2_YTD,
SUM(a.Amount3)Amount3_YTD,
SUM(a.Amount4)Amount4_YTD,
SUM(a.Amount5)Amount5_YTD
from tbl_doctor a
where FORMAT((CONVERT(smalldatetime,a.BillDate,111)),'yyyy-MM-dd') >= FORMAT((CONVERT(smalldatetime,'2012-04-01',111)),'yyyy-04-01')
AND FORMAT((CONVERT(smalldatetime,a.BillDate,111)),'yyyy-MM-dd') <= '2012-05-01'
and a.SpecialisationCode!=0
and a.Specialisation NOT IN (' ')
GROUP BY a.SpecialisationCode,a.Specialisation)YTD



LEFT OUTER JOIN

(select 
a.SpecialisationCode,
a.Specialisation,
SUM(a.DoctorFee)Revenue_DTD,
SUM(a.Amount1)Amount1_DTD,
SUM(a.Amount2)Amount2_DTD,
SUM(a.Amount3)Amount3_DTD,
SUM(a.Amount4)Amount4_DTD,
SUM(a.Amount5)Amount5_DTD
from tbl_doctor a
where FORMAT((CONVERT(smalldatetime,a.BillDate,111)),'yyyy-MM-dd') >= '2012-04-01'
  AND FORMAT((CONVERT(smalldatetime,a.BillDate,111)),'yyyy-MM-dd') <= '2012-05-01'
and a.SpecialisationCode!=0
and a.Specialisation NOT IN (' ')
GROUP BY a.SpecialisationCode,a.Specialisation)DTD
ON   DTD.SpecialisationCode=YTD.SpecialisationCode

LEFT OUTER JOIN


(select 
a.SpecialisationCode,
a.Specialisation,
SUM(a.DoctorFee)Revenue_MTD,
SUM(a.Amount1)Amount1_MTD,
SUM(a.Amount2)Amount2_MTD,
SUM(a.Amount3)Amount3_MTD,
SUM(a.Amount4)Amount4_MTD,
SUM(a.Amount5)Amount5_MTD
from tbl_doctor a
where FORMAT((CONVERT(smalldatetime,a.BillDate,111)),'yyyy-MM-dd') >= FORMAT((CONVERT(smalldatetime,'2012-05-01',111)),'yyyy-MM-01')
  AND FORMAT((CONVERT(smalldatetime,a.BillDate,111)),'yyyy-MM-dd') <= FORMAT((CONVERT(smalldatetime,eomonth('2012-05-01'),111)),'yyyy-MM-dd')
and a.SpecialisationCode!=0
and a.Specialisation NOT IN (' ')
GROUP BY a.SpecialisationCode,a.Specialisation)MTD

ON  YTD.SpecialisationCode=MTD.SpecialisationCode


LEFT OUTER JOIN

(select 
a.SpecialisationCode,
a.Specialisation,
COALESCE(SUM(a.DoctorFee),0)Revenue_Today,
SUM(a.Amount1)Amount1_Today,
SUM(a.Amount2)Amount2_Today,
SUM(a.Amount3)Amount3_Today,
SUM(a.Amount4)Amount4_Today,
SUM(a.Amount5)Amount5_Today
from tbl_doctor a
where FORMAT((CONVERT(smalldatetime,a.BillDate,111)),'yyyy-MM-dd') = '2012-05-01'
and a.SpecialisationCode!=0
and a.Specialisation NOT IN (' ')
GROUP BY a.SpecialisationCode,a.Specialisation)Today
ON  YTD.SpecialisationCode=Today.SpecialisationCode ) z
order by z.Specialisation

Answer 1

在我看来，您可以通过使用条件聚合一次性解决整个查询。

我没有太多使用 SQL Server，所以我不完全了解日期逻辑，但据我了解，您正在计算不同时间段的金额，例如自年初以来累积的金额当月，今天的金额等等。

对于这样的查询，无论如何，您都会在年初和今天之间接触所有带有BillDate 的记录。您应该能够使用类似于以下的查询。这个想法是仅当 BillDate 在时间段内时才对金额求和。

select a.SpecialisationCode
      ,a.Specialisation
      ,sum(case when a.BillDate = today then a.Amount1 end) as Amount1_Today
      ,sum(case when a.BillDate between date 'first-day-in-month' and today then a.Amount1 end) as Amount1_MTD
      ,sum(a.Amount1) as Amount1_YTD
  from tbl_doctor
 where a.SpecialisationCode!=0
   and a.Specialisation NOT IN (' ')   
   and a.BillDate between date 'first day in year'
                      and date 'today'
 group 
    by a.SpecialisationCode
      ,a.Specialisation;

如果你不能让它工作，请告诉我！