One of the arguments I need for my stored procedure is a list of acct numbers. The list could have 'All', which means all acct numbers in the database. It could have 2 acct numbers, or 20 acct numbers. Each acct# is 9 characters long. Since I don't know how many acct numbers they will select, the nvarchar may not be enough ( although it probably will be ). So, inside the stored procedure it would do a "select * from transactions where acctno in ('123456789', '223456789','323456789'), etc. What's the best data type to use for this? Thanks.