Question

How can I update multiple records in a database using one Update statement where the cases are different.

refundNumber = CASE _
WHEN salesRecords.invNo='1' AND itemNo='250' AND length(refundNumber) > 1 THEN _
concat(refundNumber, ', 88' ) Else '88' _
WHEN salesRecords.invNo='1' AND itemNo='7095' AND length(refundNumber) > 1 THEN _
concat(refundNumber, ', 88' ) Else '88'  _
END

This fails and should look like:

refundNumber = CASE _
WHEN invNo='1' AND itemNo='250' AND length(refundNumber) > 1 THEN _
concat(refundNumber, ', 88' )  _
WHEN invNo='1' AND itemNo='7095' AND length(refundNumber) > 1 THEN _
concat(refundNumber, ', 88' ) Else '88'  _
END

The difference being that the Else comes right at the end.

But it sets refundNumber on ALL records to 88.

What I am trying to do is add a value to a field named refundNumber to those items where the invNo = 'currentInvoiceNumber' AND itemNo = 'itemNumber'

BUT, since refundNumber is a text field which is meant to contain a comma separated list, I am trying to determine whether this field is empty or not, if it is, just enter the number, if it isn’t, append the number preceded by a comma to the existing field content. Hence the length(refundNumber) > 1 THEN concat(refundNumber, ', 88' ) bit.

I’ve not tested it, but I believe the VB logic I’d need would be:

IF invNo='1' And itemNo='250' THEN
    IF length(refundNumber) > 1 THEN 
        concat(refundNumber, ', 88' )  
    ELSE
        '88'
    END IF
ELSE IF invNo='1' And itemNo='7095' THEN        
    IF length(refundNumber) > 1 THEN 
        concat(refundNumber, ', 88' )  
    ELSE
        '88'
    END IF
Else
    refundNumber '- leave the field value as is because it does not comply with any of the above conditions
END IF

How could I translate this to an SQL CASE string?

Answer 1

If you don’t want to update records where the InvNo is not ‘1’ and the itemNo is not ‘250’ or ‘7095’ why not have a where clause limiting the set to this criteria? Then all you need to do concatenate refund number and 88 using a case expression, but you don’t even need this you could use:

UPDATE yourtable
SET refundNumber = ISNULL(CONCAT(NULLIF(refundNumber, ''), ', 88'), '88')
WHERE InvNo = '1'
AND itemNo in ('250', '7095')

Or use a nested case expression?