Case Statements with conditionals in SQL server

Question

I want to tweak the following SQL so the query will output the type of card (visa, mastercard, etc) as PaymentMethod instead of Credit Card.

CASE    WHEN pm.PaymentType = 1 THEN 'Cash'
        WHEN pm.PaymentType = 2 THEN 'Check' 
        WHEN pm.PaymentType = 3 THEN 'Credit Card'
        WHEN pm.PaymentType = 4 THEN 'EFT'
        WHEN pm.PaymentType = 5 THEN 'Money Order'
        WHEN pm.PaymentType = 6 THEN 'Conveyance'
        ELSE 'Unknown'
        END AS PaymentMethod, 

Can someone please point me in the right direction. I tried adding a second conditional to my case statement, but it fails out to 'Unknown' for all payment types of 3.

CASE    WHEN pm.PaymentType = 1 THEN 'Cash'
        WHEN pm.PaymentType = 2 THEN 'Check' 
        WHEN pm.PaymentType = 3 and pm.CardTypeMId = 1 THEN 'American Express'
        WHEN pm.PaymentType = 3 and pm.CardTypeMId = 2 THEN 'Discover'
        WHEN pm.PaymentType = 3 and pm.CardTypeMId = 3 THEN 'Mastercard'
        WHEN pm.PaymentType = 3 and pm.CardTypeMId = 4 THEN 'Visa'
        WHEN pm.PaymentType = 4 THEN 'EFT'
        WHEN pm.PaymentType = 5 THEN 'Money Order'
        WHEN pm.PaymentType = 6 THEN 'Conveyance'
        ELSE 'Unknown'
        END AS PaymentMethod, 

Thank you in advance for your assistance.

Answer 1

You could simplify this quite a bit.

CASE pm.PaymentType 
    WHEN 1 THEN 'Cash'
    WHEN 2 THEN 'Check' 
    WHEN 3 THEN 
        CASE pm.CardTypeMId 
            WHEN 1 THEN 'American Express'
            WHEN 2 THEN 'Discover'
            WHEN 3 THEN 'Mastercard'
            WHEN 4 THEN 'Visa'
        END
    WHEN 4 THEN 'EFT'
    WHEN 5 THEN 'Money Order'
    WHEN 6 THEN 'Conveyance'
    ELSE 'Unknown'
END AS PaymentMethod

Answer 2

You can use nested CASE

WHEN pm.PaymentType = 3 THEN 
 Case 
    WHEN pm.CardTypeMId = 1 THEN 'American Express'
    WHEN pm.CardTypeMId = 2 THEN 'Discover'
    WHEN pm.CardTypeMId = 3 THEN 'Mastercard'
    WHEN pm.CardTypeMId = 4 THEN 'Visa'
    END as CreditCard