SQL Server store multiple values in sql variable

Question

I have the following query:

select * 
from cars 
where make in ('BMW', 'Toyota', 'Nissan')

What I want to do is store the where parameters in a SQL variable.

Something like:

declare @caroptions varchar(max);
select @caroptions =  select distinct(make) from carsforsale;
print @caroptions;
select * from cars where make in (@caroptions)

Problem is the print of @caroptions only has the last result returned from:

select distinct(make) from carsforsale;

I want it to store multiple values.

Any ideas?

Answer 1

You can use a table variable:

declare @caroptions table
(
    car varchar(1000)
)

insert into @caroptions values ('BMW')
insert into @caroptions values ('Toyota')
insert into @caroptions values ('Nissan')

select * from cars where make in (select car from @caroptions)

Answer 2

I wrote about this here if you want to see it in detail. In the mean time, you can't do it exactly how you are thinking.

Your choices are:

Using the LIKE command:

DECLARE @CarOptions varchar(100)
SET @CarOptions = 'Ford, Nisan, Toyota'

SELECT *
FROM Cars
WHERE ','+@CarOptions+',' LIKE ',%'+CAST(Make AS varchar)+',%'

A spliter function

DECLARE @CarOptions varchar(100)
SET @CarOptions = 'Ford, Nisan, Toyota'

SELECT Cars.*
FROM Cars
JOIN DelimitedSplit8K (@CarOptions,',') SplitString
    ON Cars.Make = SplitString.Item

Dyanmic SQL

DECLARE @CarOptions varchar(100)
SET @CarOptions = 'Ford, Nisan, Toyota'

DECLARE @sql nvarchar(1000)

SET @sql = 'SELECT * ' + 
            'FROM Cars ' + 
            'WHERE Make IN ('+@CarOptions+') '

EXEC sp_executesql @sql

In the mean time your best option is going to be to get rid of the variable completely.

SELECT * FROM cars WHERE make IN (SELECT make FROM carsforsale );