sql查詢問題

最近在寫項目中遇到很多關於查詢的問題，寫個記錄，方便日後再查。
1.在一個字段中根據相同的值，把另一個字段的值相加

查詢出Mitm的前9位相同的PlanNum相加結果小於1000：
兩種方法：

select left(Mitm,9) Mitm,sum(PlanNum) Num  from MouthlyPlan2  
inner join Product on MouthlyPlan2.Mitm = Product.ProductCode where  Dates = '201611.0' group by left(Mitm,9)
having sum(PlanNum)<1000

select * from (
select left(Mitm,9) Mitm,sum(PlanNum) Num  from MouthlyPlan2  
inner join Product on MouthlyPlan2.Mitm = Product.ProductCode where  Dates = '201611.0' group by left(Mitm,9)
) TT where Num < 1000

2.查詢結果，兩字段相除

語句：

select *,case when 總量=0 then '0' else convert(nvarchar, round(isnull(變動量,0)*100/ 總量,2))+'%' end 計劃變動率 from (
select Dates,SUM(case when Types='MouthLyPlan' then 0 else PlanNum end) 變動量 ,isnull(sum(PlanNum),0) 總量 from MouthlyPlan2
 where Dates = '201611.0'
 group by Dates
) TT

3.查詢之和不等於0

select SUM(temp14) temp14  from PlanTableView having sum(temp14) <> 0

4.動態行轉列

語句：

DECLARE @sql VARCHAR(1000), @distinct_val VARCHAR(500) ;  
SET @sql = 'SELECT * FROM PlanTable PIVOT(SUM(PlanNum) FOR [Types] IN (' ;  
SET @distinct_val = (SELECT STUFF(( SELECT DISTINCT ',[' + [Types]+']' FROM PlanTable FOR XML PATH('')), 1, 1, '')) ;  
SET @sql = @sql + @distinct_val + '))' + ' p' + ' WHERE Dates = 201611.0  and  Version = 2.0 '
print (@sql)
EXEC(@sql)

關於GROUP BY:
http://www.cnblogs.com/rainman/archive/2013/05/01/3053703.html

5
A表
日期 金額
2014-05-01 100
2014-05-02 200
2014-05-05 300
2014-05-06 200

需要顯示出來的是這樣
2014-05-01 100
2014-05-02 200
2014-05-03 0
2014-05-04 0
2014-05-05 300
2014-05-06 200

----------------------------------------------------------------
-- Author  :fredrickhu(小F，向高手學習)
-- Date    :2014-05-29 10:32:27
-- Version:
--      Microsoft SQL Server 2012 - 11.0.2100.60 (Intel X86) 
--  Feb 10 2012 19:13:17 
--  Copyright (c) Microsoft Corporation
--  Enterprise Edition: Core-based Licensing on Windows NT 6.1 <X86> (Build 7601: Service Pack 1)
--
----------------------------------------------------------------
--> 測試數據：[A]
if object_id('[A]') is not null drop table [A]
go 
create table [A]([日期] datetime,[金額] int)
insert [A]
select '2014-05-01',100 union all
select '2014-05-02',200 union all
select '2014-05-05',300 union all
select '2014-05-06',200
--------------開始查詢--------------------------
select b.日期,isnull(a.金額,0) as 金額
from
(
select convert(varchar(10),dateadd(day,number,'2014-05-01'),120)  as 日期
from
    master..spt_values 
where 
    datediff(day,dateadd(day,number,'2014-05-01'), '2014-05-06')>=0
    and number>=0 
    and type='p')b
left join a on a.日期=b.日期
----------------結果----------------------------
/* 日期         金額
---------- -----------
2014-05-01 100
2014-05-02 200
2014-05-03 0
2014-05-04 0
2014-05-05 300
2014-05-06 200

(6 行受影響)

*/