Question

I am trying to write a stored procedure in sql server 2005 which will first check if the phone exists in Database. If a row exists, it will give me MerchantID of that row. Else, it will check for CompanyName, City, State and gets the MerchanTID, else it does not give me anything. But i have this error coming up “Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.
The ‘CheckifMerchantexists’ procedure attempted to return a status of NULL, which is not allowed. A status of 0 will be returned instead. ” Where am i doing wrong? Thank you for all your help.

ALTER PROCEDURE [dbo].[CheckifMerchantexists]
(@CompanyName varchar(50)
,@Phone varchar(15)
,@City varchar(30)
,@State varchar(2)
)

AS
BEGIN

declare @MerchantID int
set @MerchantID = (Select MerchantID from Merchant where Phone = @Phone)


IF @MerchantID = null 
Begin   
    set @MerchantID = (Select MerchantID from Merchant where CompanyName = @CompanyName  and City = @City and State = @State)
    return @MerchantID
END
else 
Begin
    return @MerchantID
End

Answer 1

You do not need to use “set” here

set @MerchantID = (Select MerchantID from Merchant where Phone = @Phone)

try replacing it with

Select @MerchantID = MerchantID from Merchant where Phone = @Phone

But note that you may not get expected results if more than one Merchant has the same phone number. You may have to consider changing your logic.