diff --git a/tests/system-test/2-query/distribute_agg_apercentile.py b/tests/system-test/2-query/distribute_agg_apercentile.py
index d61532c945e081722e6f7f536723b7a1faab60a6..fd1455ce16b8868de25d9800b73399ab0e88ec6f 100644
--- a/tests/system-test/2-query/distribute_agg_apercentile.py
+++ b/tests/system-test/2-query/distribute_agg_apercentile.py
@@ -130,7 +130,7 @@ class TDTestCase:
         tdSql.checkRows(15)
 
         # union all 
-        tdSql.query("select apercentile(c1,20) from stb1 union all select apercentile(c1,10) from stb1 ")
+        tdSql.query("select apercentile(c1,20) from stb1 union all select apercentile(c1,20) from stb1 ")
         tdSql.checkRows(2)
         tdSql.checkData(0,0,7.389181281)