diff --git a/do.go b/do.go
index cd003656..ebb5aa78 100644
--- a/do.go
+++ b/do.go
@@ -372,7 +372,7 @@ func (s *Do) related(value interface{}, foreign_keys ...string) {
 	if from_from {
 		s.where(foreign_value).query()
 	} else {
-		query := fmt.Sprintf("%v = %v", toSnake(foreign_key), foreign_value)
+		query := fmt.Sprintf("%v = %v", toSnake(foreign_key), s.addToVars(foreign_value))
 		s.where(query).query()
 	}
 }
@@ -529,6 +529,8 @@ func (s *Do) buildWhereCondition(clause map[string]interface{}) (str string) {
 		}
 	case int, int64, int32:
 		return s.primaryCondiation(s.addToVars(query))
+	case sql.NullInt64:
+		return s.primaryCondiation(s.addToVars(query.(sql.NullInt64).Int64))
 	case []int64, []int, []int32, []string:
 		str = fmt.Sprintf("(%v in (?))", s.model.primaryKeyDb())
 		clause["args"] = []interface{}{query}
@@ -558,7 +560,13 @@ func (s *Do) buildWhereCondition(clause map[string]interface{}) (str string) {
 			}
 			str = strings.Replace(str, "?", strings.Join(temp_marks, ","), 1)
 		default:
-			str = strings.Replace(str, "?", s.addToVars(arg), 1)
+			switch arg.(type) {
+			case sql.NullInt64, sql.NullFloat64, sql.NullBool, sql.NullString:
+				value := reflect.ValueOf(arg).Field(0).Interface()
+				str = strings.Replace(str, "?", s.addToVars(value), 1)
+			default:
+				str = strings.Replace(str, "?", s.addToVars(arg), 1)
+			}
 		}
 	}
 	return
@@ -616,7 +624,13 @@ func (s *Do) buildNotCondition(clause map[string]interface{}) (str string) {
 			}
 			str = strings.Replace(str, "?", strings.Join(temp_marks, ","), 1)
 		default:
-			str = strings.Replace(not_equal_sql, "?", s.addToVars(arg), 1)
+			switch arg.(type) {
+			case sql.NullInt64, sql.NullFloat64, sql.NullBool, sql.NullString:
+				value := reflect.ValueOf(arg).Field(0).Interface()
+				str = strings.Replace(not_equal_sql, "?", s.addToVars(value), 1)
+			default:
+				str = strings.Replace(not_equal_sql, "?", s.addToVars(arg), 1)
+			}
 		}
 	}
 	return
diff --git a/gorm_test.go b/gorm_test.go
index d119258a..d855f598 100644
--- a/gorm_test.go
+++ b/gorm_test.go
@@ -18,21 +18,21 @@ type User struct {
 	Birthday          time.Time // Time
 	Age               int64
 	Name              string
-	CreatedAt         time.Time // CreatedAt: Time of record is created, will be insert automatically
-	UpdatedAt         time.Time // UpdatedAt: Time of record is updated, will be updated automatically
-	DeletedAt         time.Time // DeletedAt: Time of record is deleted, refer Soft Delete for more
-	Emails            []Email   // Embedded structs
-	BillingAddress    Address   // Embedded struct
-	BillingAddressId  int64     // Embedded struct's foreign key
-	ShippingAddress   Address   // Embedded struct
-	ShippingAddressId int64     // Embedded struct's foreign key
+	CreatedAt         time.Time     // CreatedAt: Time of record is created, will be insert automatically
+	UpdatedAt         time.Time     // UpdatedAt: Time of record is updated, will be updated automatically
+	DeletedAt         time.Time     // DeletedAt: Time of record is deleted, refer Soft Delete for more
+	Emails            []Email       // Embedded structs
+	BillingAddress    Address       // Embedded struct
+	BillingAddressId  sql.NullInt64 // Embedded struct's foreign key
+	ShippingAddress   Address       // Embedded struct
+	ShippingAddressId int64         // Embedded struct's foreign key
 	CreditCard        CreditCard
 }
 
 type CreditCard struct {
 	Id        int64
 	Number    string
-	UserId    int64
+	UserId    sql.NullInt64
 	CreatedAt time.Time
 	UpdatedAt time.Time
 	DeletedAt time.Time
diff --git a/model.go b/model.go
index 2e3b3f11..90a9d591 100644
--- a/model.go
+++ b/model.go
@@ -108,7 +108,7 @@ func (m *Model) fields(operation string) (fields []Field) {
 				} else {
 					switch value.Interface().(type) {
 					case sql.NullInt64, sql.NullFloat64, sql.NullBool, sql.NullString:
-						field.IsBlank = value.FieldByName("Valid").Interface().(bool)
+						field.IsBlank = !value.FieldByName("Valid").Interface().(bool)
 					default:
 						m := &Model{data: value.Interface(), driver: m.driver}
 						fields := m.columnsHasValue("other")