Test inner joins

callbacks/query.go

@@ -28,6 +28,7 @@ func Query(db *gorm.DB) {
 			if len(db.Statement.Selects) == 0 {
 				for _, dbName := range db.Statement.Schema.DBNames {
 					clauseSelect.Columns = append(clauseSelect.Columns, clause.Column{
+						Table: db.Statement.Table,
 						Name:  dbName,
 					})
 				}
@@ -37,8 +38,9 @@ func Query(db *gorm.DB) {
 				if relation, ok := db.Statement.Schema.Relationships.Relations[name]; ok {
 					for _, s := range relation.FieldSchema.DBNames {
 						clauseSelect.Columns = append(clauseSelect.Columns, clause.Column{
-							Table: relation.FieldSchema.Table,
+							Table: relation.Name,
 							Name:  s,
+							Alias: relation.Name + "__" + s,
 						})
 					}
 
@@ -46,16 +48,16 @@ func Query(db *gorm.DB) {
 					for _, ref := range relation.References {
 						if ref.OwnPrimaryKey {
 							exprs = append(exprs, clause.Expr{
-								SQL: fmt.Sprintf("%s.%s = %s.%s", db.Statement.Schema.Table, ref.PrimaryKey.DBName, relation.FieldSchema.Table, ref.ForeignKey.DBName),
+								SQL: fmt.Sprintf("%s.%s = %s.%s", db.Statement.Schema.Table, ref.PrimaryKey.DBName, relation.Name, ref.ForeignKey.DBName),
 							})
 						} else {
 							if ref.PrimaryValue == "" {
 								exprs = append(exprs, clause.Expr{
-									SQL: fmt.Sprintf("%s.%s = %s.%s", db.Statement.Schema.Table, ref.ForeignKey.DBName, relation.FieldSchema.Table, ref.PrimaryKey.DBName),
+									SQL: fmt.Sprintf("%s.%s = %s.%s", db.Statement.Schema.Table, ref.ForeignKey.DBName, relation.Name, ref.PrimaryKey.DBName),
 								})
 							} else {
 								exprs = append(exprs, clause.Expr{
-									SQL:  fmt.Sprintf("%s.%s = ?", relation.FieldSchema.Table, ref.PrimaryKey.DBName),
+									SQL:  fmt.Sprintf("%s.%s = ?", relation.Name, ref.PrimaryKey.DBName),
 									Vars: []interface{}{ref.PrimaryValue},
 								})
 							}
@@ -64,7 +66,7 @@ func Query(db *gorm.DB) {
 
 					joins = append(joins, clause.Join{
 						Type:  clause.LeftJoin,
-						Table: clause.Table{Name: relation.FieldSchema.Table},
+						Table: clause.Table{Name: relation.FieldSchema.Table, Alias: relation.Name},
 						ON:    clause.Where{Exprs: exprs},
 					})
 				} else {

callbacks/scan.go

@@ -3,6 +3,7 @@ package callbacks
 import (
 	"database/sql"
 	"reflect"
+	"strings"
 
 	"github.com/jinzhu/gorm"
 	"github.com/jinzhu/gorm/schema"
@@ -54,12 +55,21 @@ func Scan(rows *sql.Rows, db *gorm.DB) {
 			isPtr := db.Statement.ReflectValue.Type().Elem().Kind() == reflect.Ptr
 			db.Statement.ReflectValue.Set(reflect.MakeSlice(db.Statement.ReflectValue.Type(), 0, 0))
 			fields := make([]*schema.Field, len(columns))
+			joinFields := make([][2]*schema.Field, len(columns))
 
 			for idx, column := range columns {
 				if field := db.Statement.Schema.LookUpField(column); field != nil && field.Readable {
 					fields[idx] = field
+				} else if names := strings.Split(column, "__"); len(names) > 1 {
+					if rel, ok := db.Statement.Schema.Relationships.Relations[names[0]]; ok {
+						if field := rel.FieldSchema.LookUpField(strings.Join(names[1:], "__")); field != nil && field.Readable {
+							joinFields[idx] = [2]*schema.Field{rel.Field, field}
+							continue
+						}
+					}
+					values[idx] = &sql.RawBytes{}
 				} else {
-					values[idx] = sql.RawBytes{}
+					values[idx] = &sql.RawBytes{}
 				}
 			}
 
@@ -68,6 +78,9 @@ func Scan(rows *sql.Rows, db *gorm.DB) {
 				for idx, field := range fields {
 					if field != nil {
 						values[idx] = field.ReflectValueOf(elem).Addr().Interface()
+					} else if joinFields[idx][0] != nil {
+						relValue := joinFields[idx][0].ReflectValueOf(elem)
+						values[idx] = joinFields[idx][1].ReflectValueOf(relValue).Addr().Interface()
 					}
 				}
 
@@ -86,8 +99,17 @@ func Scan(rows *sql.Rows, db *gorm.DB) {
 			for idx, column := range columns {
 				if field := db.Statement.Schema.LookUpField(column); field != nil && field.Readable {
 					values[idx] = field.ReflectValueOf(db.Statement.ReflectValue).Addr().Interface()
+				} else if names := strings.Split(column, "__"); len(names) > 1 {
+					if rel, ok := db.Statement.Schema.Relationships.Relations[names[0]]; ok {
+						relValue := rel.Field.ReflectValueOf(db.Statement.ReflectValue)
+						if field := rel.FieldSchema.LookUpField(strings.Join(names[1:], "__")); field != nil && field.Readable {
+							values[idx] = field.ReflectValueOf(relValue).Addr().Interface()
+							continue
+						}
+					}
+					values[idx] = &sql.RawBytes{}
 				} else {
-					values[idx] = sql.RawBytes{}
+					values[idx] = &sql.RawBytes{}
 				}
 			}
 

tests/joins.go

@@ -7,9 +7,75 @@ import (
 )
 
 func TestJoins(t *testing.T, db *gorm.DB) {
-	db.Migrator().DropTable(&User{})
+	db.Migrator().DropTable(&User{}, &Account{}, &Company{})
-	db.AutoMigrate(&User{})
+	db.AutoMigrate(&User{}, &Account{}, &Company{})
+
+	check := func(t *testing.T, oldUser, newUser User) {
+		if newUser.Company.ID != oldUser.Company.ID {
+			t.Errorf("Company is not equal when load with joins, loaded company id: %v", newUser.Company.ID)
+		}
+
+		if newUser.Manager == nil || newUser.Manager.ID != oldUser.Manager.ID {
+			t.Errorf("Manager is not equal when load with joins: loaded manager: %+v", newUser.Manager)
+		}
+
+		if newUser.Account.ID != oldUser.Account.ID {
+			t.Errorf("Account is not equal when load with joins, loaded account id: %v, expect: %v", newUser.Account.ID, oldUser.Account.ID)
+		}
+	}
 
 	t.Run("Joins", func(t *testing.T) {
+		user := User{
+			Name:    "joins-1",
+			Company: Company{Name: "company"},
+			Manager: &User{Name: "manager"},
+			Account: Account{Number: "account-has-one-association"},
+		}
+
+		db.Create(&user)
+
+		var user2 User
+		if err := db.Joins("Company").Joins("Manager").Joins("Account").First(&user2, "users.name = ?", user.Name).Error; err != nil {
+			t.Fatalf("Failed to load with joins, got error: %v", err)
+		}
+
+		check(t, user, user2)
+	})
+
+	t.Run("JoinsForSlice", func(t *testing.T) {
+		users := []User{{
+			Name:    "slice-joins-1",
+			Company: Company{Name: "company"},
+			Manager: &User{Name: "manager"},
+			Account: Account{Number: "account-has-one-association"},
+		}, {
+			Name:    "slice-joins-2",
+			Company: Company{Name: "company2"},
+			Manager: &User{Name: "manager2"},
+			Account: Account{Number: "account-has-one-association2"},
+		}, {
+			Name:    "slice-joins-3",
+			Company: Company{Name: "company3"},
+			Manager: &User{Name: "manager3"},
+			Account: Account{Number: "account-has-one-association3"},
+		}}
+
+		db.Create(&users)
+
+		var users2 []User
+		if err := db.Joins("Company").Joins("Manager").Joins("Account").Find(&users2, "users.name LIKE ?", "slice-joins%").Error; err != nil {
+			t.Fatalf("Failed to load with joins, got error: %v", err)
+		} else if len(users2) != len(users) {
+			t.Fatalf("Failed to load join users, got: %v, expect: %v", len(users2), len(users))
+		}
+
+		for _, u2 := range users2 {
+			for _, u := range users {
+				if u.Name == u2.Name {
+					check(t, u, u2)
+					continue
+				}
+			}
+		}
 	})
 }