SQL Server 一些查询技巧

--1.【行列转换】
--列转行
USE tempdb
GO
IF (OBJECT_ID('DEPT') IS NOT NULL)
    DROP TABLE DEPT
CREATE TABLE DEPT(NAME VARCHAR(5),COL1 INT,COL2 INT,COL3 INT,COL4 INT,COL5 INT,COL6 INT)    

INSERT INTO DEPT
SELECT 'A',10,50,20,30,0,80
UNION ALL
SELECT 'B',50,20,10,10,20,40
UNION ALL
SELECT 'C',5,0,0,10,0,80  

SELECT * FROM DEPT  

select NAME,NEWCOLUMNS,value
--into #TEMP
from DEPT
unpivot(
    value for NEWCOLUMNS in(COL1,COL2,COL3,COL4,COL5,COL6)
) as t
/*
NAME    NEWCOLUMNS  value
A   COL1    10
A   COL2    50
A   COL3    20
A   COL4    30
A   COL5    0
A   COL6    80
B   COL1    50
B   COL2    20
B   COL3    10
B   COL4    10
B   COL5    20
B   COL6    40
C   COL1    5
C   COL2    0
C   COL3    0
C   COL4    10
C   COL5    0
C   COL6    80
*/  

--行转列
select * from  #TEMP   

select * from #TEMP
PIVOT(
    max(value) for NEWCOLUMNS in(COL1,COL2,COL3,COL4,COL5,COL6)
) as t
/*
NAME    COL1    COL2    COL3    COL4    COL5    COL6
A   10  50  20  30  0   80
B   50  20  10  10  20  40
C   5   0   0   10  0   80
*/  

--2.【每行中的数值统计：每行中各列数据的最大值、最小值、平均值】
USE tempdb
GO
IF (OBJECT_ID('DEPT') IS NOT NULL)
    DROP TABLE DEPT
CREATE TABLE DEPT(NAME VARCHAR(5),COL1 INT,COL2 INT,COL3 INT,COL4 INT,COL5 INT,COL6 INT)    

INSERT INTO DEPT
SELECT 'A',10,50,20,30,0,80
UNION ALL
SELECT 'B',50,20,10,10,20,40
UNION ALL
SELECT 'C',5,0,0,10,0,80  

SELECT *
,MaxValue=(select MAX(COL) FROM (
        SELECT COL1 AS COL
        UNION ALL
        SELECT COL2
        UNION ALL
        SELECT COL3
        UNION ALL
        SELECT COL4
        UNION ALL
        SELECT COL5
        UNION ALL
        SELECT COL6 ) A)
,MINValue=(select MIN(COL) FROM (
        SELECT COL1 AS COL
        UNION ALL
        SELECT COL2
        UNION ALL
        SELECT COL3
        UNION ALL
        SELECT COL4
        UNION ALL
        SELECT COL5
        UNION ALL
        SELECT COL6 ) B)
,AVGValue=(select AVG(COL) FROM (
        SELECT COL1 AS COL
        UNION ALL
        SELECT COL2
        UNION ALL
        SELECT COL3
        UNION ALL
        SELECT COL4
        UNION ALL
        SELECT COL5
        UNION ALL
        SELECT COL6 ) c)
FROM DEPT  

/* 结果:
NAME    COL1    COL2    COL3    COL4    COL5    COL6    MaxValue    MINValue    AVGValue
A   10  50  20  30  0   80  80  0   31
B   50  20  10  10  20  40  50  10  25
C   5   0   0   10  0   80  80  0   15
*/  

--3.【每列中的数值统计】
USE tempdb
GO
IF (OBJECT_ID('DEPT') IS NOT NULL)
    DROP TABLE DEPT
CREATE TABLE DEPT(ID INT IDENTITY (1,1),VALUE INT)    

INSERT INTO DEPT(VALUE)
VALUES(90),(86),(60),(80),(100),(0),(0),(85),(80),(65)  

SELECT * FROM DEPT  

select ID,VALUE
,id = dense_rank() over(order by VALUE desc)
,比例 = VALUE*100.0/sum(VALUE)OVER()
,最大差值 =  max(VALUE)OVER() - VALUE
,最小差值 =  VALUE - min(VALUE)OVER()
from DEPT  

/*结果:
ID  VALUE   id  比例  最大差值    最小差值
5   100 1   15.479876160990 0   100
1   90  2   13.931888544891 10  90
2   86  3   13.312693498452 14  86
8   85  4   13.157894736842 15  85
9   80  5   12.383900928792 20  80
4   80  5   12.383900928792 20  80
10  65  6   10.061919504643 35  65
3   60  7   9.287925696594  40  60
6   0   8   0.000000000000  100 0
7   0   8   0.000000000000  100 0
*/  

--4.【某部门的所有上级机构或下级机构】
IF (OBJECT_ID('DEPT') IS NOT NULL)
    DROP TABLE DEPT
CREATE TABLE DEPT(ID INT,PID INT, NAME VARCHAR(20))    

INSERT INTO DEPT VALUES
(1,0,'总公司'),
(2,1,'研发部'),
(3,1,'销售部'),
(4,1,'财务部'),
(5,2,'研发一部'),
(6,2,'研发二部'),
(7,3,'销售一部'),
(8,3,'销售二部'),
(9,3,'销售三部'),
(10,5,'小组A'),
(11,5,'小组B')  

SELECT * FROM DEPT    

--求一个部门的所有下级，如[研发部] 的所有下级'
--条件:所有部门的父id都等于[研发部]的ID,取到都是下级的
;WITH D(ID,PID,NAME,LVL)
AS(
    SELECT ID,PID,NAME,0 LVL FROM DEPT WHERE NAME='研发部'
    UNION ALL
    SELECT DEPT.ID,DEPT.PID,DEPT.NAME,LVL +1
    FROM DEPT INNER JOIN D ON DEPT.PID=D.ID
)
SELECT * FROM D    

--求一个部门的所有上级，如[研发一部] 的所有上级'
;WITH D(ID,PID,NAME,LVL)
AS(
    SELECT ID,PID,NAME,0 LVL FROM DEPT WHERE NAME='研发一部'
    UNION ALL
    SELECT DEPT.ID,DEPT.PID,DEPT.NAME,LVL +1
    FROM DEPT INNER JOIN D ON DEPT.ID=D.PID
)
SELECT * FROM D    

SELECT * FROM DEPT INNER JOIN (SELECT ID,PID,NAME FROM DEPT WHERE NAME='研发部' ) TAB ON DEPT.ID=TAB.ID  

--5.【添加 删除 更新 时取出数据】
drop table #temp
SELECT * FROM DEPT  --继续用上一步的表
SELECT NAME into #temp FROM DEPT WHERE 1<>1  

SELECT * FROM #temp   

insert into #temp(NAME)
output inserted.NAME    --into tableName(colName) 输出可插入到其他表
SELECT NAME FROM DEPT   

Delete DEPT
output deleted.NAME
where PID = 3  

UPDATE #temp
SET NAME = '集团'
OUTPUT Inserted.NAME Old, Deleted.NAME New
WHERE NAME = '总公司'   

--6.【Merge into】  

/*
drop table #a;
drop table #b;
*/
create table #a (aid int null,aname varchar(10) null);
create table #b (bid int null,bname varchar(10) null);    

insert into #a values(1,'Value1');
insert into #a values(3,'Value3');
insert into #a values(4,'Value4');    

insert into #b values(1,'New Value1');
insert into #b values(2,'New Value2');
insert into #b values(3,'New Value3');    

merge into #a using #b
on #a.aid=#b.bid
when matched --and #a.aid = 1 （可增加条件）
    then update set #a.aname=#b.bname
when not matched
    then insert values(#b.bid,#b.bname)
when not matched by source then
    delete; --必须分号结束  

select * from #a;
select * from #b;    

--7.【多列查询同一值简化】  

select * from tableName
where COL1=100 or COL2=100 or COL3=100 or COL4=100 or COL5=100 or COL6=100  

--简化操作
select * from tableName where 100 in(COL1,COL2,COL3,COL4,COL5,COL6)  

--8.【同列字符相连】
use tempdb
go
--  drop table tb
create table tb(id int,value varchar(30))
go
insert into tb
values
(1,'aa'),
(1,'bb'),
(2,'aaa'),
(2,'bbb'),
(2,'ccc')   

select * from tb  

SELECT DISTINCT id,STUFF((SELECT ','+value FROM tb B WHERE A.id=B.id FOR XML PATH('')),1,1,'') AS value
FROM tb A    

/*结果:
id  value
--- -----------
1   aa,bb
2   aaa,bbb,ccc
*/  

--逆转换
use tempdb
go
--  drop table tb
create table tb(id int,value varchar(30))
go
insert into tb values(1,'aa,bb')
insert into tb values(2,'aaa,bbb,ccc')   

select * from tb  

select A.id, B.value
from(
    select id, [value] = convert(xml,' <root> <v>' + replace([value], ',', ' </v> <v>') + ' </v> </root>') from tb
)A
outer apply(
    select value = N.v.value('.', 'varchar(100)') from A.[value].nodes('/root/v') N(v)
)B   

/*结果:
id  value
--  -----
1   aa
1   bb
2   aaa
2   bbb
2   ccc
*/  

--8.【同列数值分组累加】  

drop table #temp
create table #temp(name varchar(1),value int)  

insert #temp
select 'a',1 union all
select 'b',5 union all
select 'a',3 union all
select 'a',5 union all
select 'b',9 union all
select 'b',5  

select * from #temp  

;with tabA as(
    select row_number() over(partition by name order by name) id,name,value from #temp
)
, tabB AS(
    select id,name,value,value as total from tabA WHERE id = 1
    union all
    select a.id,a.name,a.value,a.value+b.total
    from tabA a inner join tabB b on a.name=b.name and a.id=b.id+1
)
select * from tabB order by name,id  

/*结果:
id name value   total
-- ---- -----   ----
1   a   3       3
2   a   5       8
3   a   1       9
1   b   5       5
2   b   9       14
3   b   5       19
*/  

--【一条sql语句执行N次】
CREATE TABLE TB(ID INT IDENTITY (1,1),NAME VARCHAR(40))    

INSERT INTO TB(NAME) SELECT 'KK'+CONVERT(VARCHAR(5),isnull(@@IDENTITY,0)+1)
GO 10  

--【随机取出N条记录】
select top 5 * from tableName order by newid()  

年内按月累计（如：2月累计为前两个月的，3月累计为前三个月的)

CREATE TABLE T (tDate DATETIME,tValue INT)
INSERT INTO dbo.T
	SELECT '2017-01-08',10 UNION
	SELECT '2017-01-25',20 UNION
	SELECT '2017-02-11',30 UNION
	SELECT '2017-02-28',40 UNION
	SELECT '2017-03-17',50 UNION
	SELECT '2017-04-03',60 UNION
	SELECT '2017-04-20',70 UNION
	SELECT '2017-05-07',80 UNION
	SELECT '2017-05-24',90
SELECT * FROM dbo.T;

SELECT MONTH(tDate) AS 月份,
(SELECT SUM(tValue) FROM dbo.T T1  WHERE MONTH(T1.tDate)<=MONTH(T.tDate)) 累计
FROM dbo.T
GROUP BY MONTH(tDate)

tDate                   tValue
----------------------- -----------
2017-01-08 00:00:00.000 10
2017-01-25 00:00:00.000 20
2017-02-11 00:00:00.000 30
2017-02-28 00:00:00.000 40
2017-03-17 00:00:00.000 50
2017-04-03 00:00:00.000 60
2017-04-20 00:00:00.000 70
2017-05-07 00:00:00.000 80
2017-05-24 00:00:00.000 90

(9 行受影响)

月份          累计
----------- -----------
1           30
2           100
3           150
4           280
5           450

(5 行受影响)

求x个月内产品逐月库存

if object_id('[huang]') is not null drop table [huang]
go
create table [huang]([年] int,[月] int,[产品] varchar(1),[未出库数量] int)
insert [huang]
select 2013,11,'A',100 union all
select 2014,1,'A',300 union all
select 2013,10,'B',1000 union all
select 2013,11,'B',1500 union all
select 2013,12,'B',3001
--------------开始查询--------------------------
;WITH d AS
(
 SELECT CONVERT(VARCHAR(10),DATEADD(mm,number,'2013-11-01'),120)[date],b.产品
 FROM master..spt_values cross JOIN (SELECT DISTINCT 产品 FROM [huang]) b
 WHERE [type]='p' AND number>0 AND number<7  --这个7可以控制月份

),cte AS (
select ISNULL([年],YEAR(d.[date])) [年],ISNULL([月],month(d.[date])) [月],ISNULL(a.[产品],d.产品) 产品,ISNULL([未出库数量],0)[未出库数量],ROW_NUMBER()OVER(PARTITION BY ISNULL(a.[产品],d.产品) ORDER BY ISNULL([年],YEAR(d.[date])),ISNULL([月],month(d.[date]))) id
 from [huang] a full JOIN d ON a.[年]=YEAR(d.[date]) AND a.[月]=MONTH(d.[date]) AND a.[产品]=d.产品
 ) 

 SELECT [年],[月],[产品],ISNULL((SELECT SUM([未出库数量]  ) FROM cte b WHERE a.id>b.id AND a.[产品]=b.[产品]),0)[未出库数量]
  FROM cte a
 ORDER BY [产品],[年],a.月

 /*
 年           月           产品   未出库数量
----------- ----------- ---- -----------
2013        11          A    0
2013        12          A    100
2014        1           A    100
2014        2           A    400
2014        3           A    400
2014        4           A    400
2014        5           A    400
2013        10          B    0
2013        11          B    1000
2013        12          B    2500
2014        1           B    5501
2014        2           B    5501
2014        3           B    5501
2014        4           B    5501
2014        5           B    5501
 */