diff --git a/docs/en/api/metrics-query-expression.md b/docs/en/api/metrics-query-expression.md
index 29d9fdd833..a3b717887d 100644
--- a/docs/en/api/metrics-query-expression.md
+++ b/docs/en/api/metrics-query-expression.md
@@ -270,7 +270,7 @@ For example:
 If we want to query all Redis command total rates, we can use the following expression(`total_commands_rate` is a metric which recorded every command rate in labeled value):
 
 ```text
-aggregate_labels(total_commands_rate, SUM)
+aggregate_labels(total_commands_rate, sum)
 ```
 
 ### Result Type