fix issue in unnacessary quoting of fields in select statement of gdb.Model

database/gdb/gdb_model_select.go

@@ -42,10 +42,12 @@ func (m *Model) All(where ...interface{}) (Result, error) {
 		}
 		conditionWhere += softDeletingCondition
 	}
+	// DO NOT quote the m.fields where, in case of fields like:
+	// DISTINCT t.user_id uid
 	return m.doGetAll(
 		fmt.Sprintf(
 			"SELECT %s FROM %s%s",
-			m.db.QuoteString(m.fields),
+			m.fields,
 			m.tables,
 			conditionWhere+conditionExtra,
 		),
@@ -249,7 +251,9 @@ func (m *Model) Count(where ...interface{}) (int, error) {
 	}
 	countFields := "COUNT(1)"
 	if m.fields != "" && m.fields != "*" {
-		countFields = fmt.Sprintf(`COUNT(%s)`, m.db.QuoteString(m.fields))
+		// DO NOT quote the m.fields here, in case of fields like:
+		// DISTINCT t.user_id uid
+		countFields = fmt.Sprintf(`COUNT(%s)`, m.fields)
 	}
 	var (
 		softDeletingCondition                         = m.getConditionForSoftDeleting()

database/gdb/gdb_unit_z_mysql_model_test.go

@@ -2297,3 +2297,30 @@ func Test_Model_Having(t *testing.T) {
 		t.Assert(len(all), 1)
 	})
 }
+
+func Test_Model_Distinct(t *testing.T) {
+	table := createInitTable()
+	defer dropTable(table)
+
+	gtest.C(t, func(t *gtest.T) {
+		all, err := db.Table(table, "t").Fields("distinct t.id").Where("id > 1").Having("id > 8").All()
+		t.Assert(err, nil)
+		t.Assert(len(all), 2)
+	})
+}
+
+func Test_Model_Min_Max(t *testing.T) {
+	table := createInitTable()
+	defer dropTable(table)
+
+	gtest.C(t, func(t *gtest.T) {
+		value, err := db.Table(table, "t").Fields("min(t.id)").Where("id > 1").Value()
+		t.Assert(err, nil)
+		t.Assert(value.Int(), 2)
+	})
+	gtest.C(t, func(t *gtest.T) {
+		value, err := db.Table(table, "t").Fields("max(t.id)").Where("id > 1").Value()
+		t.Assert(err, nil)
+		t.Assert(value.Int(), 10)
+	})
+}