fix: update setupValuerAndSetter to use default values when pointer t…

…ypes are nil

scan.go

@@ -72,7 +72,11 @@ func (db *DB) scanIntoStruct(rows Rows, reflectValue reflect.Value, values []int
 		}
 
 		if len(joinFields) == 0 || len(joinFields[idx]) == 0 {
-			db.AddError(field.Set(db.Statement.Context, reflectValue, values[idx]))
+			if value := reflect.ValueOf(values[idx]).Elem(); field.OwnerSchema == nil && value.Kind() == reflect.Ptr && value.IsNil() {
+				db.AddError(field.Set(db.Statement.Context, reflectValue, field.DefaultValueInterface))
+			} else {
+				db.AddError(field.Set(db.Statement.Context, reflectValue, values[idx]))
+			}
 		} else { // joinFields count is larger than 2 when using join
 			var isNilPtrValue bool
 			var relValue reflect.Value

tests/go.mod

@@ -17,7 +17,7 @@ require (
 require (
 	filippo.io/edwards25519 v1.1.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/go-sql-driver/mysql v1.8.0 // indirect
+	github.com/go-sql-driver/mysql v1.8.1 // indirect
 	github.com/golang-sql/civil v0.0.0-20220223132316-b832511892a9 // indirect
 	github.com/golang-sql/sqlexp v0.1.0 // indirect
 	github.com/jackc/pgpassfile v1.0.0 // indirect

tests/scan_test.go

@@ -148,7 +148,7 @@ func TestScanRows(t *testing.T) {
 	})
 
 	if !reflect.DeepEqual(results, []Result{{Name: "ScanRowsUser2", Age: 10}, {Name: "ScanRowsUser3", Age: 20}}) {
-		t.Errorf("Should find expected results")
+		t.Errorf("Should find expected results, got %+v", results)
 	}
 
 	var ages int
@@ -158,7 +158,51 @@ func TestScanRows(t *testing.T) {
 
 	var name string
 	if err := DB.Table("users").Where("name = ?", user2.Name).Select("name").Scan(&name).Error; err != nil || name != user2.Name {
-		t.Fatalf("failed to scan ages, got error %v, ages: %v", err, name)
+		t.Fatalf("failed to scan name, got error %v, name: %v", err, name)
+	}
+}
+
+func TestScanRowsNullValuesScanToZeroValues(t *testing.T) {
+	user1 := User{Name: "ScanRowsUser1", Age: 1}
+	user2 := User{Name: "ScanRowsUser2", Age: 10}
+	user3 := User{Name: "ScanRowsUser3", Age: 0}
+	DB.Save(&user1).Save(&user2).Save(&user3)
+
+	rows, err := DB.Table("users").Where("name = ? or name = ?", user2.Name, user3.Name).Select("name, CASE WHEN age = 0 THEN NULL ELSE age END AS age").Rows()
+	if err != nil {
+		t.Errorf("Not error should happen, got %v", err)
+	}
+
+	type Result struct {
+		Name string
+		Age  int
+	}
+
+	var results []Result
+	var result Result
+	for rows.Next() {
+		if err := DB.ScanRows(rows, &result); err != nil {
+			t.Errorf("should get no error, but got %v", err)
+		}
+		results = append(results, result)
+	}
+
+	sort.Slice(results, func(i, j int) bool {
+		return strings.Compare(results[i].Name, results[j].Name) <= -1
+	})
+
+	if !reflect.DeepEqual(results, []Result{{Name: "ScanRowsUser2", Age: 10}, {Name: "ScanRowsUser3", Age: 0}}) {
+		t.Errorf("Should find expected results, got %+v", results)
+	}
+
+	var ages int
+	if err := DB.Table("users").Where("name = ? or name = ?", user2.Name, user3.Name).Select("SUM(age)").Scan(&ages).Error; err != nil || ages != 10 {
+		t.Fatalf("failed to scan ages, got error %v, ages: %v", err, ages)
+	}
+
+	var name string
+	if err := DB.Table("users").Where("name = ?", user2.Name).Select("name").Scan(&name).Error; err != nil || name != user2.Name {
+		t.Fatalf("failed to scan name, got error %v, name: %v", err, name)
 	}
 }