Define variable to use with IN operator (T-SQL)

Question

I have a Transact-SQL query that uses the IN operator. Something like this:

select * from myTable where myColumn in (1,2,3,4)

Is there a wa

Answer 1

I think you'll have to declare a string and then execute that SQL string.

Have a look at sp_executeSQL

Answer 2

DECLARE @MyList TABLE (Value INT)
INSERT INTO @MyList VALUES (1)
INSERT INTO @MyList VALUES (2)
INSERT INTO @MyList VALUES (3)
INSERT INTO @MyList VALUES (4)

SELECT *
FROM MyTable
WHERE MyColumn IN (SELECT Value FROM @MyList)

Answer 3

I know this is old now but TSQL => 2016, you can use STRING_SPLIT:

DECLARE @InList varchar(255) = 'This;Is;My;List';

WITH InList (Item) AS (
    SELECT value FROM STRING_SPLIT(@InList, ';')
)

SELECT * 
FROM [Table]
WHERE [Item] IN (SELECT Tag FROM InList)

Answer 4

Use a function like this:

CREATE function [dbo].[list_to_table] (@list varchar(4000))
returns @tab table (item varchar(100))
begin

if CHARINDEX(',',@list) = 0 or CHARINDEX(',',@list) is null
begin
    insert into @tab (item) values (@list);
    return;
end


declare @c_pos int;
declare @n_pos int;
declare @l_pos int;

set @c_pos = 0;
set @n_pos = CHARINDEX(',',@list,@c_pos);

while @n_pos > 0
begin
    insert into @tab (item) values (SUBSTRING(@list,@c_pos+1,@n_pos - @c_pos-1));
    set @c_pos = @n_pos;
    set @l_pos = @n_pos;
    set @n_pos = CHARINDEX(',',@list,@c_pos+1);
end;

insert into @tab (item) values (SUBSTRING(@list,@l_pos+1,4000));

return;
end;

Instead of using like, you make an inner join with the table returned by the function:

select * from table_1 where id in ('a','b','c')

becomes

select * from table_1 a inner join [dbo].[list_to_table] ('a,b,c') b on (a.id = b.item)

In an unindexed 1M record table the second version took about half the time...

cheers

Answer 5

If you want to do this without using a second table, you can do a LIKE comparison with a CAST:

DECLARE @myList varchar(15)
SET @myList = ',1,2,3,4,'

SELECT *
FROM myTable
WHERE @myList LIKE '%,' + CAST(myColumn AS varchar(15)) + ',%'

If the field you're comparing is already a string then you won't need to CAST.

Surrounding both the column match and each unique value in commas will ensure an exact match. Otherwise, a value of 1 would be found in a list containing ',4,2,15,'

Answer 6

This one uses PATINDEX to match ids from a table to a non-digit delimited integer list.

-- Given a string @myList containing character delimited integers 
-- (supports any non digit delimiter)
DECLARE @myList VARCHAR(MAX) = '1,2,3,4,42'

SELECT * FROM [MyTable]
    WHERE 
        -- When the Id is at the leftmost position 
        -- (nothing to its left and anything to its right after a non digit char) 
        PATINDEX(CAST([Id] AS VARCHAR)+'[^0-9]%', @myList)>0 
        OR
        -- When the Id is at the rightmost position
        -- (anything to its left before a non digit char and nothing to its right) 
        PATINDEX('%[^0-9]'+CAST([Id] AS VARCHAR), @myList)>0
        OR
        -- When the Id is between two delimiters 
        -- (anything to its left and right after two non digit chars)
        PATINDEX('%[^0-9]'+CAST([Id] AS VARCHAR)+'[^0-9]%', @myList)>0
        OR
        -- When the Id is equal to the list
        -- (if there is only one Id in the list)
        CAST([Id] AS VARCHAR)=@myList

Notes:

• when casting as varchar and not specifying byte size in parentheses the default length is 30
• % (wildcard) will match any string of zero or more characters
• ^ (wildcard) not to match
• [^0-9] will match any non digit character
• PATINDEX is an SQL standard function that returns the position of a pattern in a string