diff --git a/common.go b/common.go
index 35987ba..94122fe 100644
--- a/common.go
+++ b/common.go
@@ -97,7 +97,7 @@ func isInStringLiteral(sql, match string) bool {
 func ToString(value interface{}) string {
 	switch v := value.(type) {
 	case string:
-		return v
+		return value.(string)
 	case []byte:
 		return string(v)
 	case int, int8, int16, int32, int64:
@@ -109,7 +109,12 @@ func ToString(value interface{}) string {
 	case bool:
 		return strconv.FormatBool(v)
 	case time.Time:
-		return v.Format("2006-01-02 15:04:05")
+		//return v.Format("2006-01-02 15:04:05")
+		return value.(time.Time).Format("2006-01-02 15:04:05")
+	case interface{}:
+		return value.(string)
+	case nil:
+		return ""
 	default:
 		return fmt.Sprintf("%v", v)
 	}