Getting values of comma separated fields in SQL Server - sql-server

Question

I have comma separated column which represents the ids of cities like:
ID | Name
1 | 1,2,3
2 | 2,3,4
I want to make query to get name of the this value field. There is City Table which has two columns: id and name of cities
EXPECTED OUTPUT
ID | VALUES
1 | mumbai,delhi,pune
2 | delhi,pune,chennai
I can make a query if there is only one id in a column like:
select data.id,city.name from data,city where data.values=city.cityid
but I am not getting how to retrieve the data if there are multiple comma-separated values in one field.

Answer 1

The easy way is to convert CSV values to rows for each Id, join that with CITY table and convert back to CSV values. I have written the logic inside the query.
;WITH CTE1 AS
(
-- Convert CSV to rows
SELECT Id,LTRIM(RTRIM(Split.a.value('.', 'VARCHAR(100)'))) 'NAME'
FROM
(
-- To change ',' to any other delimeter, just change ',' before '</M><M>' to your desired one
SELECT Id,CAST ('<M>' + REPLACE(Name, ',', '</M><M>') + '</M>' AS XML) AS Data
FROM #TEMP
) AS A
CROSS APPLY Data.nodes ('/M') AS Split(a)
)
,CTE2 AS
(
-- Now join the values in rows with Id in CITY table
SELECT T.ID,T.NAME,C.CITYNAME
FROM CTE1 T
JOIN #CITY C ON T.NAME=C.ID
)
-- Now convert back to CSV format
SELECT DISTINCT ID,
SUBSTRING(
(SELECT ', ' + CITYNAME
FROM CTE2 I
WHERE I.Id=O.Id
FOR XML PATH('')),2,200000) [VALUES]
FROM CTE2 O
Click here to view result

Answer 2

to do this please do following sections:
1-Create Function to get table of comma separate value in each row
CREATE FUNCTION [dbo].[fn_Split](
#ForigenKey INT,
#String NVARCHAR (4000),
#Delimiter NVARCHAR(10)
)
RETURNS #ValueTable TABLE ([ID] INT IDENTITY NOT NULL,FID int null,[Value] NVARCHAR(4000))
BEGIN
DECLARE #NextString NVARCHAR(4000)
DECLARE #Pos INT
DECLARE #NextPos INT
DECLARE #CommaCheck NVARCHAR(1)
--Initialize
SET #NextString = ''
SET #CommaCheck = RIGHT(#String,1)
--Check for trailing Comma, if not exists, INSERT
--if (#CommaCheck <> #Delimiter )
SET #String = #String + #Delimiter
--Get position of first Comma
SET #Pos = CHARINDEX(#Delimiter,#String)
SET #NextPos = LEN(#Delimiter)
--Loop while there is still a comma in the String of levels
WHILE (#pos <> 0)
BEGIN
SET #NextString = SUBSTRING(#String, 1, #Pos - 1)
INSERT INTO #ValueTable ( FID,[Value]) VALUES (#ForigenKey ,#NextString)
SET #String = SUBSTRING(#String,#pos + LEN(#Delimiter),LEN(#String))
SET #NextPos = #Pos
SET #pos = CHARINDEX(#Delimiter,#String)
END
RETURN
END
GO
2- create Concat Aggregate with the folwing link
Concat Aggregate
3- you can get your data with below select
DECLARE #ID INT,#Name NVARCHAR(4000)
DECLARE #ValueTable table ([ID] int NOT NULL,[Value] INT)
DECLARE mycur CURSOR FOR
SELECT TOP(1000) ID,Name FROM TableA
OPEN mycur
FETCH NEXT FROM mycur INTO #ID,#Name
WHILE(##FETCH_STATUS=0)
BEGIN
INSERT INTO #ValueTable
( ID, Value )
SELECT #ID,Value FROM dbo.fn_Split(#Name,',')
FETCH NEXT FROM mycur INTO #ID,#Name
END
CLOSE mycur
DEALLOCATE mycur
SELECT * FROM #ValueTable
SELECT ID,dbo.ConcatAggregate(CityName) FROM #ValueTable
inner join city on value=cityid GROUP BY ID