Add test for count with orderby and limit (go-xorm#880)

* add test for count with orderby and limit

* fix the bug

Author: lunny

session_find.go

@@ -161,7 +161,7 @@ func (session *Session) find(rowsSlicePtr interface{}, condiBean ...interface{})
 		}
 
 		args = append(session.statement.joinArgs, condArgs...)
-		sqlStr, err = session.statement.genSelectSQL(columnStr, condSQL, true)
+		sqlStr, err = session.statement.genSelectSQL(columnStr, condSQL, true, true)
 		if err != nil {
 			return err
 		}

session_query.go

@@ -70,7 +70,7 @@ func (session *Session) genQuerySQL(sqlorArgs ...interface{}) (string, []interfa
 	}
 
 	args := append(session.statement.joinArgs, condArgs...)
-	sqlStr, err := session.statement.genSelectSQL(columnStr, condSQL, true)
+	sqlStr, err := session.statement.genSelectSQL(columnStr, condSQL, true, true)
 	if err != nil {
 		return "", nil, err
 	}

session_stats_test.go

@@ -158,3 +158,28 @@ func TestSQLCount(t *testing.T) {
 	assert.NoError(t, err)
 	assert.EqualValues(t, 0, total)
 }
+
+func TestCountWithOthers(t *testing.T) {
+	assert.NoError(t, prepareEngine())
+
+	type CountWithOthers struct {
+		Id   int64
+		Name string
+	}
+
+	assertSync(t, new(CountWithOthers))
+
+	_, err := testEngine.Insert(&CountWithOthers{
+		Name: "orderby",
+	})
+	assert.NoError(t, err)
+
+	_, err = testEngine.Insert(&CountWithOthers{
+		Name: "limit",
+	})
+	assert.NoError(t, err)
+
+	total, err := testEngine.OrderBy("id desc").Limit(1).Count(new(CountWithOthers))
+	assert.NoError(t, err)
+	assert.EqualValues(t, 2, total)
+}

statement.go

@@ -971,7 +971,7 @@ func (statement *Statement) genGetSQL(bean interface{}) (string, []interface{},
 		return "", nil, err
 	}
 
-	sqlStr, err := statement.genSelectSQL(columnStr, condSQL, true)
+	sqlStr, err := statement.genSelectSQL(columnStr, condSQL, true, true)
 	if err != nil {
 		return "", nil, err
 	}
@@ -1001,7 +1001,7 @@ func (statement *Statement) genCountSQL(beans ...interface{}) (string, []interfa
 			selectSQL = "count(*)"
 		}
 	}
-	sqlStr, err := statement.genSelectSQL(selectSQL, condSQL, false)
+	sqlStr, err := statement.genSelectSQL(selectSQL, condSQL, false, false)
 	if err != nil {
 		return "", nil, err
 	}
@@ -1026,15 +1026,15 @@ func (statement *Statement) genSumSQL(bean interface{}, columns ...string) (stri
 		return "", nil, err
 	}
 
-	sqlStr, err := statement.genSelectSQL(sumSelect, condSQL, true)
+	sqlStr, err := statement.genSelectSQL(sumSelect, condSQL, true, true)
 	if err != nil {
 		return "", nil, err
 	}
 
 	return sqlStr, append(statement.joinArgs, condArgs...), nil
 }
 
-func (statement *Statement) genSelectSQL(columnStr, condSQL string, needLimit bool) (a string, err error) {
+func (statement *Statement) genSelectSQL(columnStr, condSQL string, needLimit, needOrderBy bool) (a string, err error) {
 	var distinct string
 	if statement.IsDistinct && !strings.HasPrefix(columnStr, "count") {
 		distinct = "DISTINCT "
@@ -1101,9 +1101,10 @@ func (statement *Statement) genSelectSQL(columnStr, condSQL string, needLimit bo
 			}
 
 			var orderStr string
-			if len(statement.OrderStr) > 0 {
+			if needOrderBy && len(statement.OrderStr) > 0 {
 				orderStr = " ORDER BY " + statement.OrderStr
 			}
+
 			var groupStr string
 			if len(statement.GroupByStr) > 0 {
 				groupStr = " GROUP BY " + statement.GroupByStr
@@ -1129,7 +1130,7 @@ func (statement *Statement) genSelectSQL(columnStr, condSQL string, needLimit bo
 	if statement.HavingStr != "" {
 		a = fmt.Sprintf("%v %v", a, statement.HavingStr)
 	}
-	if statement.OrderStr != "" {
+	if needOrderBy && statement.OrderStr != "" {
 		a = fmt.Sprintf("%v ORDER BY %v", a, statement.OrderStr)
 	}
 	if needLimit {