SQL Server procedure declare a list

You could declare a variable as a temporary table like this:

declare @myList table (Id int)

Which means you can use the insert statement to populate it with values:

insert into @myList values (1), (2), (5), (7), (10)

Then your select statement can use either the in statement:

select * from DBTable
where id in (select Id from @myList)

Or you could join to the temporary table like this:

select *
from DBTable d
join @myList t on t.Id = d.Id

And if you do something like this a lot then you could consider defining a user-defined table type so you could then declare your variable like this:

declare @myList dbo.MyTableType

That is not possible with a normal query since the in clause needs separate values and not a single value containing a comma separated list. One solution would be a dynamic query

declare @myList varchar(100)
set @myList = '1,2,5,7,10'
exec('select * from DBTable where id IN (' + @myList + ')')

You can convert the list of passed values into a table valued parameter and then select against this list

DECLARE @list NVARCHAR(MAX)
SET @list = '1,2,5,7,10';

DECLARE @pos INT
DECLARE @nextpos INT
DECLARE @valuelen INT
DECLARE @tbl TABLE (number int NOT NULL)

SELECT @pos = 0, @nextpos = 1;

WHILE @nextpos > 0
BEGIN
    SELECT @nextpos = charindex(',', @list, @pos + 1)
    SELECT @valuelen = CASE WHEN @nextpos > 0
                            THEN @nextpos
                            ELSE len(@list) + 1
                        END - @pos - 1
    INSERT @tbl (number)
        VALUES (convert(int, substring(@list, @pos + 1, @valuelen)))
    SELECT @pos = @nextpos;
END

SELECT * FROM DBTable WHERE id IN (SELECT number FROM @tbl);

In this example the string passed in '1,2,5,7,10' is split by the commas and each value is added as a new row within the @tbl table variable. This can then be selected against using standard SQL.

If you intend to reuse this functionality you could go further and convert this into a function.

SQL Server procedure declare a list

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