Select id, name from A where name<>lower(name) collate SQL_Latin1_General_CP1_CS_AS

Select id, A.name, B.name from A inner join B on A.name=B.name where A.name<>B.name collate SQL_Latin1_General_CP1_CS_AS 

SELECT  SUM(population),
        CASE country
                WHEN '中国'     THEN '亚洲'
                WHEN '印度'     THEN '亚洲'
                WHEN '日本'     THEN '亚洲'
                WHEN '美国'     THEN '北美洲'
                WHEN '加拿大'  THEN '北美洲'
                WHEN '墨西哥'  THEN '北美洲'
        ELSE '其他' END
FROM    Table_A
GROUP BY CASE country
                WHEN '中国'     THEN '亚洲'
                WHEN '印度'     THEN '亚洲'
                WHEN '日本'     THEN '亚洲'
                WHEN '美国'     THEN '北美洲'
                WHEN '加拿大'  THEN '北美洲'
                WHEN '墨西哥'  THEN '北美洲'
        ELSE '其他' END;

SELECT
        CASE WHEN salary <= 500 THEN '1'
             WHEN salary > 500 AND salary <= 600  THEN '2'
             WHEN salary > 600 AND salary <= 800  THEN '3'
             WHEN salary > 800 AND salary <= 1000 THEN '4'
        ELSE NULL END salary_class,
        COUNT(*)
FROM    Table_A
GROUP BY
        CASE WHEN salary <= 500 THEN '1'
             WHEN salary > 500 AND salary <= 600  THEN '2'
             WHEN salary > 600 AND salary <= 800  THEN '3'
             WHEN salary > 800 AND salary <= 1000 THEN '4'
        ELSE NULL END;

SELECT country,
       SUM( CASE WHEN sex = '1' THEN 
                      population ELSE 0 END),  --male population
       SUM( CASE WHEN sex = '2' THEN 
                      population ELSE 0 END)   --female population
FROM  Table_A
GROUP BY country;

select cast(1.23 as int) --return 1
select convert( int,1.23) --return 1

DECLARE @startnum INT=1000 --start
DECLARE @endnum INT=1020 --end 
;
WITH gen AS (
    SELECT @startnum AS num
    UNION ALL
    --change number+ i to adjust gap i
    SELECT num+3 FROM gen WHERE num+1<=@endnum 
)
SELECT * FROM gen
option (maxrecursion 10000)

;WITH Split(stpos,endpos)
        AS(
            SELECT 0 AS stpos, CHARINDEX(',','Alice,Jack,Tom') AS endpos 
            UNION ALL
            SELECT endpos+1, CHARINDEX(',','Alice,Jack,Tom',endpos+1) FROM Split WHERE endpos > 0
        )  
        --LTRIM RTRIM to get rid of white space before start or after end of str
        SELECT RTRIM(LTRIM(SUBSTRING('Alice,Jack,Tom',stpos,COALESCE(NULLIF(endpos,0),LEN('Alice,Jack,Tom')+1)-stpos))) as name into #temp
        FROM Split

SELECT * into #temp FROM (VALUES (1,'Alice'),(2,'Jack'),(3,'Tom')) AS t(id,name)

Select id, name, 'placeholder' as sex into #temp from A

--0=1 to not copy any rows
Select id, name into #temp from A where 0=1 
 
--the above query equals to 
select id, name into #temp from #temp1
delete from #temp1

create table #tmpStudent(Id int IDENTITY(1,1) PRIMARY KEY,Name varchar(50),Age int) insert into #tmpStudent select id,name,age from #tmpStudent

DECLARE @temp Table ( Id int, Name varchar(20), Age int )

select GETDATE()
select GETUTCDATE()
select cast(GETDATE() as date)  --date only
SELECT convert(date, GETDATE() ) --date only

-- add or minus is on day basis
select GETDATE()+1 --tomorrow
select GETDATE()-1 --yesterday
 
-- need to be 24.0 to return float
select GETDATE()+1.0/24 --next hour
select GETDATE()-1.0/24/2 --Last 30 min

--result is already datetime
select DATEADD(yy,-2,'07/23/2009 13:23:44') --2 years ago
select DATEADD(mm,5, DATEADD(dd,10,GETDATE())) --5 month and 10 days later

select DATEDIFF(mi,GETDATE()+1.0/24,  GETDATE()-1.0/24)  -- return -120
select DATEDIFF(dd,'2019-11-23', '2019-12-23')  --return 30

select cast('2019-10-23 23:30:59:883' as datetime) --'yyyy-mm-dd' 
select cast('2019/10/23 23:30:59:883' as datetime) --'yyyy/mm/dd' use ':' for ms
select cast('10-23-2019 23:30:59.883' as datetime) --'mm-dd-yyyy' use '.' for ms
select cast('10/23/2019 23:30:59.883' as datetime) --'mm/dd/yyyy'
--same to use convert
SELECT convert(date, '07/23/2009' )

--these pairs are same to get dd,mm,yy part of a datetime, return integer
select Datepart(dd,GETDATE()),day(GETDATE())
select Datepart(mm,GETDATE()),month(GETDATE())
select Datepart(yyyy,GETDATE()),year(GETDATE())
select Datepart(dy,'2019-08-11') --get day of year: 223
 
select datename(mm,'2000-5-17')  --return 'May'
select datename(weekday,'2000-5-17') --return 'Wednesday'

-- not working!!!! return '2019-05-17', as it detect input is string, 103 is ignored
select convert(varchar, '2019-05-17', 103)
--input is datetime, reutrn formatted string '17/05/2019'
select convert(varchar, cast('2019-05-17' as datetime), 103)

select * from students where id in (
    select id FROM students
    group by id having count(*)>1
)

select * from students a
right join (
    select firstname, lastname from students
    group by firstname, lastname having count(*)>1
) b
on a.firstname=b.firstname and a.lastname=b.lastname

select * from students except(
    select a.id --need to select all columns here
          ,a.firstname
          ,a.lastname
          ,a.dob from students a
    right join (
        select firstname, lastname from students 
        group by firstname, lastname having count(*)>1
    ) b
    on a.firstname=b.firstnameand a.lastname =b.lastname 
)

select distinct * from tableName --save the result equals to delete duplicated rows already

delete from #temp
where id not in(
    select   max(id)   from   #temp
    group   by   col1, col2 --the columns used when checking duplicate
    having count(*)>1
)

WITH tempVw AS (
    SELECT 
        *,
        ROW_NUMBER() OVER ( --over() is required for Row_Number()
            PARTITION BY --this reset the rowNumber to 1 for different group
                col1, col2 --which used as identifier to check duplicate
            ORDER BY  --order by is required in Over()
                col1, col2 --keep same as above
        ) row_num
     FROM 
        YourTable
)
delete FROM tempVw WHERE row_num > 1
select * from YourTable --duplicated rows should be removed in original table

--Use views to add rowId for table without unique id
with tempVw as(
    select ROW_NUMBER() over (order by SurveyTypeid, surveyid ) as rowid,*
    from YourTable
)
--define 2 views together, tempVw2 is all duplicated rows
,tempVw2 as (
    select rowid,a.col1,a.col2
    from tempVw a
    right join (
        select col1, col2 from tempVw
        group by col1, col2 having count(*)>1
    ) b
    on a.col1=b.col1 and a.col2=b.col2
) 
--query after view, delete rows in view will delete original table
delete  from tempVw where rowid in (
    --return all duplicated rows except 1 row for each group that we will keep
    select rowid from tempVw2 where rowid not in (
        --return 1 row for each identifier of duplicated rows
        select min (rowid) from tempVw2 group by col1, col2 having count(*)>1
    )
)
select * from YourTable --duplicated rows should be removed in original table

Select * from A except Select * from B 

Select * from A except Select * from B union all Select * from B except Select * from A  

Select * from A Intersect Select * from B

declare @temp table(id int,Name varchar(50),sex varchar(10))
declare @sql varchar(max)= 'select id,name,''male'' from student where id<3'
insert into @temp exec (@sql)

Select col1, col2 from A where exists (Select 1 from B where id=99) --inside exists you can select 1 or anything, it will return TRUE equally

Select id, name from A where not exists (Select 1 from B where B.id=A.id) 
--this equals to use IN keyword
Select id, name from A where id not in (Select id from B) 

--student number for each class
select class,count (*) as total from Student group by class 
--average score for each class
select class,avg(score) as AvgScore from Student group by class 
--highest score for each class
select class,max(score) as HighestScore from Student group by class 
--total donation for each class
select class,sum(donation) as TotalDonation from Student group by class 

SELECT * --INTO #Cars
FROM OPENROWSET('Microsoft.ACE.OLEDB.12.0',
'Excel 12.0 Xml;HDR=YES;Database=C:\cars.xlsx','SELECT * FROM [sheet1$]');

insert into #temp(id,name) values (1,'Alice'),(2, 'Jack')

insert into #temp(id,name, sex) select id, name,'male' from students where sex=1 

declare @temp table(id int,Name varchar(50),sex varchar(10))
declare @sql varchar(max)= 'select id,name,''male'' from student where id<3'
insert into @temp exec (@sql)

Select * from A cross join B
Select * from A,B --same as above

Select * from where name LIKE ' [^.$#@-]_ [a-z0-9]%'

select NEWID() --315FC5A3-BE07-41BB-BE4F-75055729FA5B

SELECT CONVERT(varchar(255), NEWID())

SELECT RAND() -- 0<=decimal<1 
SELECT RAND()*15+5; -- 5<=decimal<20 (if include 20 need *16)
 
SELECT FLOOR(22.6) --22
SELECT CEILING(22.6) --23
SELECT ROUND(22.6,0) -- 23.0
SELECT ROUND(22.6,-1) --20.0 

create table #Student (id int, Class int, Score int )
insert into #Student values(1,1,88)
insert into #Student values(2,1,66)
insert into #Student values(3,2,30)
insert into #Student values(4,2,70)
insert into #Student values(5,2,60)
insert into #Student values(6,3,70)
insert into #Student values(7,3,80)

select *,row_number() over(order by class) rowid from #Student  

select *,rank() over(order by class) rowid from #Student --if 1st has 2 pp, next is 3rd
select *,dense_rank() over(order by class) rowid from #Student --if 1st has 2 pp, next is 2nd

select *,row_number() over(partition by class order by class) rowid from #Student

select * from (
    select *,row_number() over(partition by class order by class) rowid from #Student  
)a where rowid<2
 
select * from (
    select *,row_number() over(partition by class order by class) rowid from #Student  
)a where rowid=2

select left('hello world',5) --return: hello
select right('hello world!',6) --return:world!

select substring('hello world',7,5) --return: world

select REPLACE('123456','34','new') --return 12new56
select stuff('123456',3,2,'new') --same as above, start index=3, length=2

--split 'hello world' by space
select left('hello world',CHARINDEX(' ','hello world')-1) 
select right('hello world',len('hello world')-CHARINDEX(' ','hello world'))

SELECT LTRIM('   Sample   '); --return 'Sample '
SELECT RTRIM('   Sample   '); --return ' Sample'

--char(13)+CHAR(10) = enter
print 'first line'+char(13)+CHAR(10)+'Second line' --2 lines
--char(9) is tab, the outsode replace delete all space
print REPLACE(REPLACE(REPLACE(REPLACE('first line
Second line',CHAR(13),''),CHAR(10),''),CHAR(9),''),' ','')

SELECT PATINDEX('%[mo]%', 'W3Schools.com'); --return m or o which appear first

select REPLICATE('hello world ',3) --return: hello world hello world hello world  

select REVERSE('1234567') --return 7654321

select 'a'+SPACE(5)+'b' --return a     b

select top 2 * from ( --between 4 and 5, 5-4+1=2
    select top 5 * from #Student order by score desc)a
order by score  

-- if there are multiple highest score, will select highest score
select * from (
    select *,row_number() over( order by score desc) rowid from #Student  
)a where rowid=2
--if there are multiple highest score, still select second highest score 
select * from (
    select *,rank() over( order by score desc) rowid from #Student  
)a where rowid=2
-- rowid between m and n -- rows between order of the m place to n place 

Declare @isDebug bit=1
begin tran
 
-- insert/update/delete queries    
 
if @isDebug=1 --test run
begin
    rollback tran
end
else -- prod run
begin
    commit tran
end

Declare @isDebug bit=1
BEGIN TRY
    BEGIN tran    
        if @isDebug=0 --test run
        begin 
            -- insert/update/delete queries    
        end
        else --prod run
        begin
            -- insert/update/delete queries
        end
 
    COMMIT tran --commit if above code has no error
END TRY
BEGIN CATCH
    ROLLBACK tran --if any error jump to this to rollback
    select ERROR_NUMBER() as ErrorNumber, ERROR_MESSAGE() as ErrorMessage, ERROR_PROCEDURE() as ErrorProcedure
END CATCH

UPDATE  a
SET     a.marks = b.marks
FROM    tempDataView a
        INNER JOIN tempData b
            ON a.Name = b.Name

with StudentVw as(
    select top 100 ROW_NUMBER() over (order by SurveyTypeid, surveyid ) as rowid,*
    from ##temp order by channelid -- if use order by must have top keyword
)
select * from StudentVw --must come with a query and only 1 query