diff --git a/tests/system-test/2-query/interp.py b/tests/system-test/2-query/interp.py
index 0fe86e44eb..5550519e05 100644
--- a/tests/system-test/2-query/interp.py
+++ b/tests/system-test/2-query/interp.py
@@ -552,37 +552,54 @@ class TDTestCase:
         tdSql.checkData(1, 0, 15)
 
         tdLog.printNoPrefix("==========step9:test multi-interp cases")
-        tdSql.query(f"select interp(c0),interp(c1),interp(c2),interp(c3) from {dbname}.{tbname} range('2020-02-10 00:00:05', '2020-02-12 00:00:05') every(1d) fill(null)")
+        tdSql.query(f"select interp(c0),interp(c1),interp(c2),interp(c3) from {dbname}.{tbname} range('2020-02-09 00:00:05', '2020-02-13 00:00:05') every(1d) fill(null)")
+        tdSql.checkRows(5)
+        tdSql.checkCols(4)
+
+        for i in range (tdSql.queryCols):
+          tdSql.checkData(0, i, None)
+          tdSql.checkData(1, i, None)
+          tdSql.checkData(2, i, 15)
+          tdSql.checkData(3, i, None)
+          tdSql.checkData(4, i, None)
+
+        tdSql.query(f"select interp(c0),interp(c1),interp(c2),interp(c3) from {dbname}.{tbname} range('2020-02-09 00:00:05', '2020-02-13 00:00:05') every(1d) fill(value, 1)")
+        tdSql.checkRows(5)
+        tdSql.checkCols(4)
+
+        for i in range (tdSql.queryCols):
+          tdSql.checkData(0, i, 1)
+          tdSql.checkData(1, i, 1)
+          tdSql.checkData(2, i, 15)
+          tdSql.checkData(3, i, 1)
+          tdSql.checkData(4, i, 1)
+
+        tdSql.query(f"select interp(c0),interp(c1),interp(c2),interp(c3) from {dbname}.{tbname} range('2020-02-09 00:00:05', '2020-02-13 00:00:05') every(1d) fill(prev)")
+        tdSql.checkRows(5)
+        tdSql.checkCols(4)
+
+        for i in range (tdSql.queryCols):
+          tdSql.checkData(0, i, 5)
+          tdSql.checkData(1, i, 5)
+          tdSql.checkData(2, i, 15)
+          tdSql.checkData(3, i, 15)
+          tdSql.checkData(4, i, 15)
+
+        tdSql.query(f"select interp(c0),interp(c1),interp(c2),interp(c3) from {dbname}.{tbname} range('2020-02-09 00:00:05', '2020-02-13 00:00:05') every(1d) fill(next)")
         tdSql.checkRows(3)
         tdSql.checkCols(4)
-        tdSql.checkData(0, 0, None)
-        tdSql.checkData(1, 0, 15)
-        tdSql.checkData(2, 0, None)
 
-        tdSql.query(f"select interp(c0),interp(c1),interp(c2),interp(c3) from {dbname}.{tbname} range('2020-02-10 00:00:05', '2020-02-12 00:00:05') every(1d) fill(value, 1)")
-        tdSql.checkRows(3)
-        tdSql.checkCols(4)
-        tdSql.checkData(0, 0, 1)
-        tdSql.checkData(1, 0, 15)
-        tdSql.checkData(2, 0, 1)
+        for i in range (tdSql.queryCols):
+          tdSql.checkData(0, i, 15)
+          tdSql.checkData(1, i, 15)
+          tdSql.checkData(2, i, 15)
 
-        tdSql.query(f"select interp(c0),interp(c1),interp(c2),interp(c3) from {dbname}.{tbname} range('2020-02-10 00:00:05', '2020-02-12 00:00:05') every(1d) fill(prev)")
-        tdSql.checkRows(3)
-        tdSql.checkCols(4)
-        tdSql.checkData(0, 0, 5)
-        tdSql.checkData(1, 0, 15)
-        tdSql.checkData(2, 0, 15)
-
-        tdSql.query(f"select interp(c0),interp(c1),interp(c2),interp(c3) from {dbname}.{tbname} range('2020-02-10 00:00:05', '2020-02-12 00:00:05') every(1d) fill(next)")
-        tdSql.checkRows(2)
-        tdSql.checkCols(4)
-        tdSql.checkData(0, 0, 15)
-        tdSql.checkData(1, 0, 15)
-
-        tdSql.query(f"select interp(c0),interp(c1),interp(c2),interp(c3) from {dbname}.{tbname} range('2020-02-10 00:00:05', '2020-02-12 00:00:05') every(1d) fill(linear)")
+        tdSql.query(f"select interp(c0),interp(c1),interp(c2),interp(c3) from {dbname}.{tbname} range('2020-02-09 00:00:05', '2020-02-13 00:00:05') every(1d) fill(linear)")
         tdSql.checkRows(1)
         tdSql.checkCols(4)
-        tdSql.checkData(0, 0, 15)
+
+        for i in range (tdSql.queryCols):
+            tdSql.checkData(0, i, 15)
 
         tdLog.printNoPrefix("==========step10:test error cases")