diff --git a/session_stats.go b/session_stats.go
index bb89d4c2..df02e95a 100644
--- a/session_stats.go
+++ b/session_stats.go
@@ -4,7 +4,11 @@
 
 package xorm
 
-import "database/sql"
+import (
+	"database/sql"
+	"errors"
+	"reflect"
+)
 
 // Count counts the records. bean's non-empty fields
 // are conditions.
@@ -43,20 +47,26 @@ func (session *Session) Count(bean ...interface{}) (int64, error) {
 	return 0, err
 }
 
-// Sum call sum some column. bean's non-empty fields are conditions.
-func (session *Session) Sum(bean interface{}, columnName string) (float64, error) {
+// sum call sum some column. bean's non-empty fields are conditions.
+func (session *Session) sum(res interface{}, bean interface{}, columnNames ...string) error {
 	defer session.resetStatement()
 	if session.isAutoClose {
 		defer session.Close()
 	}
 
+	v := reflect.ValueOf(res)
+	if v.Kind() != reflect.Ptr {
+		return errors.New("need a pointer to a variable")
+	}
+
+	var isSlice = v.Elem().Kind() == reflect.Slice
 	var sqlStr string
 	var args []interface{}
 	var err error
 	if len(session.statement.RawSQL) == 0 {
-		sqlStr, args, err = session.statement.genSumSQL(bean, columnName)
+		sqlStr, args, err = session.statement.genSumSQL(bean, columnNames...)
 		if err != nil {
-			return 0, err
+			return err
 		}
 	} else {
 		sqlStr = session.statement.RawSQL
@@ -65,120 +75,44 @@ func (session *Session) Sum(bean interface{}, columnName string) (float64, error
 
 	session.queryPreprocess(&sqlStr, args...)
 
-	var res float64
-	if session.isAutoCommit {
-		err = session.DB().QueryRow(sqlStr, args...).Scan(&res)
+	if isSlice {
+		if session.isAutoCommit {
+			err = session.DB().QueryRow(sqlStr, args...).ScanSlice(res)
+		} else {
+			err = session.tx.QueryRow(sqlStr, args...).ScanSlice(res)
+		}
 	} else {
-		err = session.tx.QueryRow(sqlStr, args...).Scan(&res)
+		if session.isAutoCommit {
+			err = session.DB().QueryRow(sqlStr, args...).Scan(res)
+		} else {
+			err = session.tx.QueryRow(sqlStr, args...).Scan(res)
+		}
 	}
 
 	if err == sql.ErrNoRows || err == nil {
-		return res, nil
+		return nil
 	}
-	return 0, err
+	return err
+}
+
+// Sum call sum some column. bean's non-empty fields are conditions.
+func (session *Session) Sum(bean interface{}, columnName string) (res float64, err error) {
+	return res, session.sum(&res, bean, columnName)
 }
 
 // SumInt call sum some column. bean's non-empty fields are conditions.
-func (session *Session) SumInt(bean interface{}, columnName string) (int64, error) {
-	defer session.resetStatement()
-	if session.isAutoClose {
-		defer session.Close()
-	}
-
-	var sqlStr string
-	var args []interface{}
-	var err error
-	if len(session.statement.RawSQL) == 0 {
-		sqlStr, args, err = session.statement.genSumSQL(bean, columnName)
-		if err != nil {
-			return 0, err
-		}
-	} else {
-		sqlStr = session.statement.RawSQL
-		args = session.statement.RawParams
-	}
-
-	session.queryPreprocess(&sqlStr, args...)
-
-	var res int64
-	if session.isAutoCommit {
-		err = session.DB().QueryRow(sqlStr, args...).Scan(&res)
-	} else {
-		err = session.tx.QueryRow(sqlStr, args...).Scan(&res)
-	}
-
-	if err == sql.ErrNoRows || err == nil {
-		return res, nil
-	}
-	return 0, err
+func (session *Session) SumInt(bean interface{}, columnName string) (res int64, err error) {
+	return res, session.sum(&res, bean, columnName)
 }
 
 // Sums call sum some columns. bean's non-empty fields are conditions.
 func (session *Session) Sums(bean interface{}, columnNames ...string) ([]float64, error) {
-	defer session.resetStatement()
-	if session.isAutoClose {
-		defer session.Close()
-	}
-
-	var sqlStr string
-	var args []interface{}
-	var err error
-	if len(session.statement.RawSQL) == 0 {
-		sqlStr, args, err = session.statement.genSumSQL(bean, columnNames...)
-		if err != nil {
-			return nil, err
-		}
-	} else {
-		sqlStr = session.statement.RawSQL
-		args = session.statement.RawParams
-	}
-
-	session.queryPreprocess(&sqlStr, args...)
-
 	var res = make([]float64, len(columnNames), len(columnNames))
-	if session.isAutoCommit {
-		err = session.DB().QueryRow(sqlStr, args...).ScanSlice(&res)
-	} else {
-		err = session.tx.QueryRow(sqlStr, args...).ScanSlice(&res)
-	}
-
-	if err == sql.ErrNoRows || err == nil {
-		return res, nil
-	}
-	return nil, err
+	return res, session.sum(&res, bean, columnNames...)
 }
 
 // SumsInt sum specify columns and return as []int64 instead of []float64
 func (session *Session) SumsInt(bean interface{}, columnNames ...string) ([]int64, error) {
-	defer session.resetStatement()
-	if session.isAutoClose {
-		defer session.Close()
-	}
-
-	var sqlStr string
-	var args []interface{}
-	var err error
-	if len(session.statement.RawSQL) == 0 {
-		sqlStr, args, err = session.statement.genSumSQL(bean, columnNames...)
-		if err != nil {
-			return nil, err
-		}
-	} else {
-		sqlStr = session.statement.RawSQL
-		args = session.statement.RawParams
-	}
-
-	session.queryPreprocess(&sqlStr, args...)
-
 	var res = make([]int64, len(columnNames), len(columnNames))
-	if session.isAutoCommit {
-		err = session.DB().QueryRow(sqlStr, args...).ScanSlice(&res)
-	} else {
-		err = session.tx.QueryRow(sqlStr, args...).ScanSlice(&res)
-	}
-
-	if err == sql.ErrNoRows || err == nil {
-		return res, nil
-	}
-	return nil, err
+	return res, session.sum(&res, bean, columnNames...)
 }