diff --git a/dbpool.go b/dbpool.go
index 65e7951..92f12cf 100644
--- a/dbpool.go
+++ b/dbpool.go
@@ -235,7 +235,20 @@ func (this *dbPool) joinWhere(sql *string, params *[]string, whereKv [][]string)
 }
 
 func (this *dbPool) joinUpdateFields(fieldsKv [][]string, params *[]string) string {
-	return ""
+	sql := ""
+	for index, items := range fieldsKv {
+		suffix := ""
+		if index + 1 < len(fieldsKv) {
+			suffix = ","
+		}
+		if items[0][0] == '!' {
+			sql += " `" + items[0][1:] + "`=" + items[1] + suffix
+		} else {
+			sql += " `" + items[0] + "`=?" + suffix
+			*params = append(*params, items[1])
+		}
+	}
+	return sql
 }
 
 func (this *dbPool) joinInsertFields(fieldsKv [][]string, params *[]string) string {