Comma separated list different ways

creating table with sample data.

create table CommaSeparatedList

(

ID int identity(1,1) primary key,

Name varchar(100)

)

insert into CommaSeparatedList (Name)

values('rakesh'),('raju'),('ravi')

Method-1:

Using ISNULL :

declare @commalist varchar(max)=null

select @commalist=isnull((@commalist+','),'')+cast(ID as varchar(max)) from CommaSeparatedList

select @commalist

output:

1,2,3

Method-2:

Using COALESCE :

declare @commalist varchar(max)=null

select @commalist=coalesce(@commalist+',','')+cast(ID as varchar(max)) from CommaSeparatedList

select @commalist

output:

1,2,3

Method-3:

Using FOR XML PATH :

select stuff((select distinct ','+cast(ID as varchar(max)) from CommaSeparatedList

group by ','+cast(ID as varchar(max))

for xml path('')),1,1,'')

output:

1,2,3

Comments

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Difference between LEN and DATALENGTH

LEN: LEN function returns the number of characters in a variable .it also removes the trailing spaces and then then return the length. Example-1: DECLARE @Name VARCHAR ( 20 )= 'rakesh' SELECT LEN ( @Name ) as [len] Output: Example-2: DECLARE @Name VARCHAR ( 20 )= 'rakesh ' SELECT LEN ( @Name ) as [len] Output: When we observe above variable assigned 'rakesh ' string after that added 3 spaces . Len function removes trailing spaces not leading spaces. DATALENGTH : DATALENG function returns the number of bytes occupy in a variable .it also considered the spaces also. Example-1: DECLARE @Name VARCHAR ( 20 )= 'rakesh' SELECT DATALENGTH ( @Name ) as [DataLength] Output: Example-2: DECLARE @Name VARCHAR ( 20 )= ' rakesh ' SELECT DATALENGTH ( @Name ) as [DataLength] Output: In above example before ' r ' and after ...

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