What is the difference between the number of returned items and not returned items with the full price of under 16947.7?
full price of under 16947.7 refers to l_extendedprice < 16947.7; returned item refers to l_returnflag = 'R'; not returned item refers to l_returnflag = 'A' OR l_returnflag = 'N'; difference = subtract(count(l_linenumber where l_returnflag = 'A' OR l_returnflag = 'N'), count(l_linenumber where l_returnflag = 'R')) where l_extendedprice < 16947.7
SELECT SUM(IIF(l_returnflag = 'A', 1, 0)) - SUM(IIF(l_returnflag = 'N', 1, 0)) AS diff FROM lineitem WHERE l_extendedprice < 16947.7