optimize: remove unless function (#369)

remove unless function

pkg/datasource/sql/types/image.go

@@ -20,7 +20,6 @@ package types
 import (
 	"encoding/base64"
 	"encoding/json"
-	"fmt"
 	"reflect"
 	"time"
 )
@@ -262,10 +261,6 @@ func (c *ColumnImage) UnmarshalJSON(data []byte) error {
 	return nil
 }
 
-func getTypeStr(src interface{}) string {
-	return fmt.Sprintf("%T", src)
-}
-
 func (c *ColumnImage) GetActualValue() interface{} {
 	if c.Value == nil {
 		return nil