增加了发放优惠卷

api/dao/Coupon.go

@@ -115,3 +115,21 @@ func (r *CouponDao) GetCouponListByValidTime(maps interface{}, startTime, endTim
 	}
 	return m, nil
 }
+
+// Inc 自增
+func (r *CouponDao) Inc(tx *gorm.DB, couponId int64, field string, numeral int) error {
+	err := tx.Model(&model.Coupon{}).Where("coupon_id = ?", couponId).UpdateColumn(field, gorm.Expr(field+" + ?", numeral)).Error
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// Dec 自减
+func (r *CouponDao) Dec(tx *gorm.DB, couponId int64, field string, numeral int) error {
+	err := tx.Model(&model.Coupon{}).Where("coupon_id = ?", couponId).UpdateColumn(field, gorm.Expr(field+" - ?", numeral)).Error
+	if err != nil {
+		return err
+	}
+	return nil
+}