diff --git a/PostgreSQL/prism/prism.sql b/PostgreSQL/prism/prism.sql
index 37e537d..eb91d42 100644
--- a/PostgreSQL/prism/prism.sql
+++ b/PostgreSQL/prism/prism.sql
@@ -149,7 +149,7 @@ where action_id = (select action_id from actions where action = 'block-break')
 group by world_id, x, y, z
 order by count((world_id, x, y, z)) desc;
 
--- 1天内，非明确实体触发的block-break行为，按坐标分组
+-- 1天内，cause_id为null的block-break行为，按坐标分组
 select world_id, x, y, z, count((world_id, x, y, z))
 from activities
 where action_id = (select action_id from actions where action = 'block-break')