Aggregate function message

I get the message "you tried to execute a query that does not include the specified expression 'customerid' as part of the aggregate function. I have seen several answers to this and they don't make sense. I have 4 fields in my table customerid, bluesales, whitesales total sales and tried the query CUSTCOLOR: Sum([BLUESALES_AMT])/Sum([WHITESALES_AMT])*100. I don't know how to get 'customerid' to be included.
Asked May 07, 2010

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