When you use aggregate functions, you are creating new variables, even if you are using the same names. As a result, you need to associate date formats with the date variables. The following works: libname fromweb " someplace or other"; proc sql; create table want as select min(bank_number) as bank_number, min (account_number) as account_number, min(country) as country, min(branch_number) as branch_number, min(currency_code) as currency_code, max (post_date) as post_date format=date9., max (effective_date) as effective_date format=date9., sum (principal) as sum_principal, sum (write_off_total) as net_write_off_total from fromweb.post_this_data group by account_number ; quit; Hope this helps.
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