[TD-6046]<fix> fix ts top/bottom error

tests/pytest/functions/function_derivative.py

@@ -63,6 +63,16 @@ class TDTestCase:
                 tdSql.checkData(3, 1, "2018-09-17 09:01:20.000")
                 tdSql.checkData(3, 3, "2018-09-17 09:01:20.000")
 
+                tdSql.query("select ts,derivative(col1, 10, 1),ts from tb1")
+                tdSql.checkRows(2)
+                tdSql.checkData(0, 0, "2018-09-17 09:00:10.000")
+                tdSql.checkData(0, 1, "2018-09-17 09:00:10.000")
+                tdSql.checkData(0, 3, "2018-09-17 09:00:10.000")
+                tdSql.checkData(1, 0, "2018-09-17 09:00:20.009")
+                tdSql.checkData(1, 1, "2018-09-17 09:00:20.009")
+                tdSql.checkData(1, 3, "2018-09-17 09:00:20.009")
+
+
                 tdSql.query("select ts from(select ts,derivative(col, 10s, 0) from stb group by tbname)")
 
                 tdSql.checkData(0, 0, "2018-09-17 09:00:10.000")

tests/pytest/functions/function_diff.py

@@ -95,6 +95,24 @@ class TDTestCase:
         tdSql.error("select diff(col14) from test")
 
 
+        tdSql.query("select ts,diff(col1),ts from test1")
+        tdSql.checkRows(10)
+        tdSql.checkData(0, 0, "2018-09-17 09:00:00.000")
+        tdSql.checkData(0, 1, "2018-09-17 09:00:00.000")
+        tdSql.checkData(0, 3, "2018-09-17 09:00:00.000")
+        tdSql.checkData(9, 0, "2018-09-17 09:00:00.009")
+        tdSql.checkData(9, 1, "2018-09-17 09:00:00.009")
+        tdSql.checkData(9, 3, "2018-09-17 09:00:00.009")
+
+        tdSql.query("select ts,diff(col1),ts from test group by tbname")
+        tdSql.checkRows(10)
+        tdSql.checkData(0, 0, "2018-09-17 09:00:00.000")
+        tdSql.checkData(0, 1, "2018-09-17 09:00:00.000")
+        tdSql.checkData(0, 3, "2018-09-17 09:00:00.000")
+        tdSql.checkData(9, 0, "2018-09-17 09:00:00.009")
+        tdSql.checkData(9, 1, "2018-09-17 09:00:00.009")
+        tdSql.checkData(9, 3, "2018-09-17 09:00:00.009")
+
         tdSql.query("select diff(col1) from test1")
         tdSql.checkRows(10)