i need some help with a query, also to find out if this is even
possible with sql. currently i have a table with the following data:
CustomerNumber CustomerBranch
123 NULL
123 1
123 2
221 NULL
221 5
555 1
555 9
125 NULL
now in this data, CustomerNumber and CustomerBranch are the keys, each
customer MUST have a CustomerBranch with null, those NULL
CustomerBranch's represent the company headquaters, while the ones
with numbers are the other offices. Occassionally data is missing, in
the example above CustomerNumber 555 does not have a NULL
CustomerBranch, this is wrong. Is there anyway in SQL to find all
those CustomerNumbers who do not have a null, there can only be one
null per CustomerNumber. i was thinking about using a
count(CustomerBranch) but not sure how to write it to count all those
CustomerBranchs per CustomerNumber that are equal to 0, if that's the
right way to do it.
Thank you.