Fix alias keyword with Table, close #3104

chainable_api.go

@@ -2,6 +2,7 @@ package gorm
 
 import (
 	"fmt"
+	"regexp"
 	"strings"
 
 	"gorm.io/gorm/clause"
@@ -40,9 +41,19 @@ func (db *DB) Clauses(conds ...clause.Expression) (tx *DB) {
 	return
 }
 
+var tableRegexp = regexp.MustCompile("(?i).+ AS (\\w+)\\s*$")
+
 // Table specify the table you would like to run db operations
 func (db *DB) Table(name string) (tx *DB) {
 	tx = db.getInstance()
+	if strings.Contains(name, " ") {
+		tx.Statement.FullTable = name
+		if results := tableRegexp.FindStringSubmatch(name); len(results) == 2 {
+			tx.Statement.Table = results[1]
+			return
+		}
+	}
+
 	tx.Statement.Table = name
 	return
 }

statement.go

@@ -19,6 +19,7 @@ import (
 // Statement statement
 type Statement struct {
 	*DB
+	FullTable            string
 	Table                string
 	Model                interface{}
 	Unscoped             bool
@@ -69,7 +70,11 @@ func (stmt *Statement) QuoteTo(writer clause.Writer, field interface{}) {
 	switch v := field.(type) {
 	case clause.Table:
 		if v.Name == clause.CurrentTable {
+			if stmt.FullTable != "" {
+				writer.WriteString(stmt.FullTable)
+			} else {
 				stmt.DB.Dialector.QuoteTo(writer, stmt.Table)
+			}
 		} else if v.Raw {
 			writer.WriteString(v.Name)
 		} else {
@@ -374,6 +379,7 @@ func (stmt *Statement) Build(clauses ...string) {
 func (stmt *Statement) Parse(value interface{}) (err error) {
 	if stmt.Schema, err = schema.Parse(value, stmt.DB.cacheStore, stmt.DB.NamingStrategy); err == nil && stmt.Table == "" {
 		stmt.Table = stmt.Schema.Table
+		stmt.FullTable = stmt.Schema.Table
 	}
 	return err
 }

tests/sql_builder_test.go

@@ -24,6 +24,22 @@ func TestRow(t *testing.T) {
 	if age != 10 {
 		t.Errorf("Scan with Row, age expects: %v, got %v", user2.Age, age)
 	}
+
+	table := "gorm.users"
+	if DB.Dialector.Name() != "mysql" {
+		table = "users" // other databases doesn't support select with `database.table`
+	}
+
+	DB.Table(table).Where(map[string]interface{}{"name": user2.Name}).Update("age", 20)
+
+	row = DB.Table(table+" as u").Where("u.name = ?", user2.Name).Select("age").Row()
+	if err := row.Scan(&age); err != nil {
+		t.Fatalf("Failed to scan age, got %v", err)
+	}
+
+	if age != 20 {
+		t.Errorf("Scan with Row, age expects: %v, got %v", user2.Age, age)
+	}
 }
 
 func TestRows(t *testing.T) {