Cause . . . . . : &2 operands remain available for selection operators and &3 truth values remain available for Boolean operators. The selection expression must use all available operands and must result in one truth value. Either too many operands are specified or operators are missing from selection type &1. Selection type 1 indicates record selection, selection type 2 indicates group by selection, selection type 3 indicates case selection, and selection type 4 indicates join selection.