Passing a varchar full of comma delimited values to a SQL Server IN function

Of course if you're lazy like me, you could just do this:

Declare @Ids varchar(50) Set @Ids = ',1,2,3,5,4,6,7,98,234,'

Select * from sometable
 where Charindex(','+cast(tableid as varchar(8000))+',', @Ids) > 0

No Table No Function No Loop

Building on the idea of parsing your list into a table our DBA suggested using XML.

Declare @Ids varchar(50)
Set @Ids = ‘1,2,3,5,4,6,7,98,234’

DECLARE @XML XML
SET @XML = CAST('<i>' + REPLACE(@Ids, ',', '</i><i>') + '</i>' AS XML)

SELECT * 
FROM
    SomeTable 
    INNER JOIN @XML.nodes('i') x(i) 
        ON  SomeTable .Id = x.i.value('.', 'VARCHAR(MAX)')

These seems to have the same performance as @KM's answer but, I think, a lot simpler.

Don't use a function that loops to split a string!, my function below will split a string very fast, with no looping!

Before you use my function, you need to set up a "helper" table, you only need to do this one time per database:

CREATE TABLE Numbers
(Number int  NOT NULL,
    CONSTRAINT PK_Numbers PRIMARY KEY CLUSTERED (Number ASC)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]
DECLARE @x int
SET @x=0
WHILE @x<8000
BEGIN
    SET @x=@x+1
    INSERT INTO Numbers VALUES (@x)
END

use this function to split your string, which does not loop and is very fast:

CREATE FUNCTION [dbo].[FN_ListToTable]
(
     @SplitOn              char(1)              --REQUIRED, the character to split the @List string on
    ,@List                 varchar(8000)        --REQUIRED, the list to split apart
)
RETURNS
@ParsedList table
(
    ListValue varchar(500)
)
AS
BEGIN

/**
Takes the given @List string and splits it apart based on the given @SplitOn character.
A table is returned, one row per split item, with a column name "ListValue".
This function workes for fixed or variable lenght items.
Empty and null items will not be included in the results set.


Returns a table, one row per item in the list, with a column name "ListValue"

EXAMPLE:
----------
SELECT * FROM dbo.FN_ListToTable(',','1,12,123,1234,54321,6,A,*,|||,,,,B')

    returns:
        ListValue  
        -----------
        1
        12
        123
        1234
        54321
        6
        A
        *
        |||
        B

        (10 row(s) affected)

**/



----------------
--SINGLE QUERY-- --this will not return empty rows
----------------
INSERT INTO @ParsedList
        (ListValue)
    SELECT
        ListValue
        FROM (SELECT
                  LTRIM(RTRIM(SUBSTRING(List2, number+1, CHARINDEX(@SplitOn, List2, number+1)-number - 1))) AS ListValue
                  FROM (
                           SELECT @SplitOn + @List + @SplitOn AS List2
                       ) AS dt
                      INNER JOIN Numbers n ON n.Number < LEN(dt.List2)
                  WHERE SUBSTRING(List2, number, 1) = @SplitOn
             ) dt2
        WHERE ListValue IS NOT NULL AND ListValue!=''



RETURN

END --Function FN_ListToTable

you can use this function as a table in a join:

SELECT
    Col1, COl2, Col3...
    FROM  YourTable
        INNER JOIN FN_ListToTable(',',@YourString) s ON  YourTable.ID = s.ListValue

Here is your example:

Select * from sometable where tableid in(SELECT ListValue FROM dbo.FN_ListToTable(',',@Ids) s)

You can create a function that returns a table.

so your statement would be something like

select * from someable 
 join Splitfunction(@ids) as splits on sometable.id = splits.id

Here is a simular function.

CREATE FUNCTION [dbo].[FUNC_SplitOrderIDs]
(
    @OrderList varchar(500)
)
RETURNS 
@ParsedList table
(
    OrderID int
)
AS
BEGIN
    DECLARE @OrderID varchar(10), @Pos int

    SET @OrderList = LTRIM(RTRIM(@OrderList))+ ','
    SET @Pos = CHARINDEX(',', @OrderList, 1)

    IF REPLACE(@OrderList, ',', '') <> ''
    BEGIN
        WHILE @Pos > 0
        BEGIN
            SET @OrderID = LTRIM(RTRIM(LEFT(@OrderList, @Pos - 1)))
            IF @OrderID <> ''
            BEGIN
                INSERT INTO @ParsedList (OrderID) 
                VALUES (CAST(@OrderID AS int)) --Use Appropriate conversion
            END
            SET @OrderList = RIGHT(@OrderList, LEN(@OrderList) - @Pos)
            SET @Pos = CHARINDEX(',', @OrderList, 1)

        END
    END 
    RETURN
END