diff --git a/internal/statements/expr.go b/internal/statements/expr.go
new file mode 100644
index 00000000..b44c96ca
--- /dev/null
+++ b/internal/statements/expr.go
@@ -0,0 +1,93 @@
+// Copyright 2019 The Xorm Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package statements
+
+import (
+	"fmt"
+	"strings"
+
+	"xorm.io/builder"
+	"xorm.io/xorm/schemas"
+)
+
+// ErrUnsupportedExprType represents an error with unsupported express type
+type ErrUnsupportedExprType struct {
+	tp string
+}
+
+func (err ErrUnsupportedExprType) Error() string {
+	return fmt.Sprintf("Unsupported expression type: %v", err.tp)
+}
+
+// Expr represents an SQL express
+type Expr struct {
+	ColName string
+	Arg     interface{}
+}
+
+func (expr *Expr) WriteArgs(w *builder.BytesWriter) error {
+	switch arg := expr.Arg.(type) {
+	case *builder.Builder:
+		if _, err := w.WriteString("("); err != nil {
+			return err
+		}
+		if err := arg.WriteTo(w); err != nil {
+			return err
+		}
+		if _, err := w.WriteString(")"); err != nil {
+			return err
+		}
+	case string:
+		if arg == "" {
+			arg = "''"
+		}
+		if _, err := w.WriteString(fmt.Sprintf("%v", arg)); err != nil {
+			return err
+		}
+	default:
+		if _, err := w.WriteString("?"); err != nil {
+			return err
+		}
+		w.Append(arg)
+	}
+	return nil
+}
+
+type exprParams []Expr
+
+func (exprs exprParams) ColNames() []string {
+	var cols = make([]string, 0, len(exprs))
+	for _, expr := range exprs {
+		cols = append(cols, expr.ColName)
+	}
+	return cols
+}
+
+func (exprs *exprParams) Add(name string, arg interface{}) {
+	*exprs = append(*exprs, Expr{name, arg})
+}
+
+func (exprs exprParams) IsColExist(colName string) bool {
+	for _, expr := range exprs {
+		if strings.EqualFold(schemas.CommonQuoter.Trim(expr.ColName), schemas.CommonQuoter.Trim(colName)) {
+			return true
+		}
+	}
+	return false
+}
+
+func (exprs exprParams) WriteArgs(w *builder.BytesWriter) error {
+	for i, expr := range exprs {
+		if err := expr.WriteArgs(w); err != nil {
+			return err
+		}
+		if i != len(exprs)-1 {
+			if _, err := w.WriteString(","); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
diff --git a/internal/statements/expr_param.go b/internal/statements/expr_param.go
deleted file mode 100644
index d0c355d3..00000000
--- a/internal/statements/expr_param.go
+++ /dev/null
@@ -1,127 +0,0 @@
-// Copyright 2019 The Xorm Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package statements
-
-import (
-	"fmt"
-	"strings"
-
-	"xorm.io/builder"
-	"xorm.io/xorm/schemas"
-)
-
-// ErrUnsupportedExprType represents an error with unsupported express type
-type ErrUnsupportedExprType struct {
-	tp string
-}
-
-func (err ErrUnsupportedExprType) Error() string {
-	return fmt.Sprintf("Unsupported expression type: %v", err.tp)
-}
-
-type exprParam struct {
-	colName string
-	arg     interface{}
-}
-
-type exprParams struct {
-	ColNames []string
-	Args     []interface{}
-}
-
-func (exprs *exprParams) Len() int {
-	return len(exprs.ColNames)
-}
-
-func (exprs *exprParams) addParam(colName string, arg interface{}) {
-	exprs.ColNames = append(exprs.ColNames, colName)
-	exprs.Args = append(exprs.Args, arg)
-}
-
-func (exprs *exprParams) IsColExist(colName string) bool {
-	for _, name := range exprs.ColNames {
-		if strings.EqualFold(schemas.CommonQuoter.Trim(name), schemas.CommonQuoter.Trim(colName)) {
-			return true
-		}
-	}
-	return false
-}
-
-func (exprs *exprParams) getByName(colName string) (exprParam, bool) {
-	for i, name := range exprs.ColNames {
-		if strings.EqualFold(name, colName) {
-			return exprParam{name, exprs.Args[i]}, true
-		}
-	}
-	return exprParam{}, false
-}
-
-func (exprs *exprParams) WriteArgs(w *builder.BytesWriter) error {
-	for i, expr := range exprs.Args {
-		switch arg := expr.(type) {
-		case *builder.Builder:
-			if _, err := w.WriteString("("); err != nil {
-				return err
-			}
-			if err := arg.WriteTo(w); err != nil {
-				return err
-			}
-			if _, err := w.WriteString(")"); err != nil {
-				return err
-			}
-		case string:
-			if arg == "" {
-				arg = "''"
-			}
-			if _, err := w.WriteString(fmt.Sprintf("%v", arg)); err != nil {
-				return err
-			}
-		default:
-			if _, err := w.WriteString("?"); err != nil {
-				return err
-			}
-			w.Append(arg)
-		}
-		if i != len(exprs.Args)-1 {
-			if _, err := w.WriteString(","); err != nil {
-				return err
-			}
-		}
-	}
-	return nil
-}
-
-func (exprs *exprParams) writeNameArgs(w *builder.BytesWriter) error {
-	for i, colName := range exprs.ColNames {
-		if _, err := w.WriteString(colName); err != nil {
-			return err
-		}
-		if _, err := w.WriteString("="); err != nil {
-			return err
-		}
-
-		switch arg := exprs.Args[i].(type) {
-		case *builder.Builder:
-			if _, err := w.WriteString("("); err != nil {
-				return err
-			}
-			if err := arg.WriteTo(w); err != nil {
-				return err
-			}
-			if _, err := w.WriteString("("); err != nil {
-				return err
-			}
-		default:
-			w.Append(exprs.Args[i])
-		}
-
-		if i+1 != len(exprs.ColNames) {
-			if _, err := w.WriteString(","); err != nil {
-				return err
-			}
-		}
-	}
-	return nil
-}
diff --git a/internal/statements/insert.go b/internal/statements/insert.go
index 6cbbbeda..367dbdc9 100644
--- a/internal/statements/insert.go
+++ b/internal/statements/insert.go
@@ -59,7 +59,7 @@ func (statement *Statement) GenInsertSQL(colNames []string, args []interface{})
 			return "", nil, err
 		}
 
-		if err := statement.dialect.Quoter().JoinWrite(buf.Builder, append(colNames, exprs.ColNames...), ","); err != nil {
+		if err := statement.dialect.Quoter().JoinWrite(buf.Builder, append(colNames, exprs.ColNames()...), ","); err != nil {
 			return "", nil, err
 		}
 
@@ -79,7 +79,7 @@ func (statement *Statement) GenInsertSQL(colNames []string, args []interface{})
 				return "", nil, err
 			}
 
-			if len(exprs.Args) > 0 {
+			if len(exprs) > 0 {
 				if _, err := buf.WriteString(","); err != nil {
 					return "", nil, err
 				}
@@ -112,7 +112,7 @@ func (statement *Statement) GenInsertSQL(colNames []string, args []interface{})
 				return "", nil, err
 			}
 
-			if len(exprs.Args) > 0 {
+			if len(exprs) > 0 {
 				if _, err := buf.WriteString(","); err != nil {
 					return "", nil, err
 				}
@@ -152,7 +152,7 @@ func (statement *Statement) GenInsertMapSQL(columns []string, args []interface{}
 		return "", nil, err
 	}
 
-	if err := statement.dialect.Quoter().JoinWrite(buf.Builder, append(columns, exprs.ColNames...), ","); err != nil {
+	if err := statement.dialect.Quoter().JoinWrite(buf.Builder, append(columns, exprs.ColNames()...), ","); err != nil {
 		return "", nil, err
 	}
 
@@ -166,7 +166,7 @@ func (statement *Statement) GenInsertMapSQL(columns []string, args []interface{}
 			return "", nil, err
 		}
 
-		if len(exprs.Args) > 0 {
+		if len(exprs) > 0 {
 			if _, err := buf.WriteString(","); err != nil {
 				return "", nil, err
 			}
@@ -190,7 +190,7 @@ func (statement *Statement) GenInsertMapSQL(columns []string, args []interface{}
 			return "", nil, err
 		}
 
-		if len(exprs.Args) > 0 {
+		if len(exprs) > 0 {
 			if _, err := buf.WriteString(","); err != nil {
 				return "", nil, err
 			}
diff --git a/internal/statements/statement.go b/internal/statements/statement.go
index 3dd036a6..a52c6ca2 100644
--- a/internal/statements/statement.go
+++ b/internal/statements/statement.go
@@ -324,9 +324,9 @@ func (statement *Statement) TableName() string {
 // Incr Generate  "Update ... Set column = column + arg" statement
 func (statement *Statement) Incr(column string, arg ...interface{}) *Statement {
 	if len(arg) > 0 {
-		statement.IncrColumns.addParam(column, arg[0])
+		statement.IncrColumns.Add(column, arg[0])
 	} else {
-		statement.IncrColumns.addParam(column, 1)
+		statement.IncrColumns.Add(column, 1)
 	}
 	return statement
 }
@@ -334,9 +334,9 @@ func (statement *Statement) Incr(column string, arg ...interface{}) *Statement {
 // Decr Generate  "Update ... Set column = column - arg" statement
 func (statement *Statement) Decr(column string, arg ...interface{}) *Statement {
 	if len(arg) > 0 {
-		statement.DecrColumns.addParam(column, arg[0])
+		statement.DecrColumns.Add(column, arg[0])
 	} else {
-		statement.DecrColumns.addParam(column, 1)
+		statement.DecrColumns.Add(column, 1)
 	}
 	return statement
 }
@@ -344,9 +344,9 @@ func (statement *Statement) Decr(column string, arg ...interface{}) *Statement {
 // SetExpr Generate  "Update ... Set column = {expression}" statement
 func (statement *Statement) SetExpr(column string, expression interface{}) *Statement {
 	if e, ok := expression.(string); ok {
-		statement.ExprColumns.addParam(column, statement.dialect.Quoter().Replace(e))
+		statement.ExprColumns.Add(column, statement.dialect.Quoter().Replace(e))
 	} else {
-		statement.ExprColumns.addParam(column, expression)
+		statement.ExprColumns.Add(column, expression)
 	}
 	return statement
 }
diff --git a/session_update.go b/session_update.go
index 0adac25e..9e4cddb1 100644
--- a/session_update.go
+++ b/session_update.go
@@ -224,35 +224,35 @@ func (session *Session) Update(bean interface{}, condiBean ...interface{}) (int6
 
 	// for update action to like "column = column + ?"
 	incColumns := session.statement.IncrColumns
-	for i, colName := range incColumns.ColNames {
-		colNames = append(colNames, session.engine.Quote(colName)+" = "+session.engine.Quote(colName)+" + ?")
-		args = append(args, incColumns.Args[i])
+	for _, expr := range incColumns {
+		colNames = append(colNames, session.engine.Quote(expr.ColName)+" = "+session.engine.Quote(expr.ColName)+" + ?")
+		args = append(args, expr.Arg)
 	}
 	// for update action to like "column = column - ?"
 	decColumns := session.statement.DecrColumns
-	for i, colName := range decColumns.ColNames {
-		colNames = append(colNames, session.engine.Quote(colName)+" = "+session.engine.Quote(colName)+" - ?")
-		args = append(args, decColumns.Args[i])
+	for _, expr := range decColumns {
+		colNames = append(colNames, session.engine.Quote(expr.ColName)+" = "+session.engine.Quote(expr.ColName)+" - ?")
+		args = append(args, expr.Arg)
 	}
 	// for update action to like "column = expression"
 	exprColumns := session.statement.ExprColumns
-	for i, colName := range exprColumns.ColNames {
-		switch tp := exprColumns.Args[i].(type) {
+	for _, expr := range exprColumns {
+		switch tp := expr.Arg.(type) {
 		case string:
 			if len(tp) == 0 {
 				tp = "''"
 			}
-			colNames = append(colNames, session.engine.Quote(colName)+"="+tp)
+			colNames = append(colNames, session.engine.Quote(expr.ColName)+"="+tp)
 		case *builder.Builder:
 			subQuery, subArgs, err := session.statement.GenCondSQL(tp)
 			if err != nil {
 				return 0, err
 			}
-			colNames = append(colNames, session.engine.Quote(colName)+"=("+subQuery+")")
+			colNames = append(colNames, session.engine.Quote(expr.ColName)+"=("+subQuery+")")
 			args = append(args, subArgs...)
 		default:
-			colNames = append(colNames, session.engine.Quote(colName)+"=?")
-			args = append(args, exprColumns.Args[i])
+			colNames = append(colNames, session.engine.Quote(expr.ColName)+"=?")
+			args = append(args, expr.Arg)
 		}
 	}