ajust get min condition

go/gopath/src/fohow.com/apps/helpers/promotion_helper.go

@@ -125,6 +125,10 @@ func max(vals ...int64) int64 {
 func min(vals ...int64) int64 {
 	min := int64(0)
 	for _, val := range vals {
+		if val <= int64(0) {
+			min = int64(0)
+			break
+		}
 		if val <= min || min == int64(0) {
 			min = val
 		}