add case for stable about sample

tests/system-test/2-query/sample.py

@@ -798,6 +798,35 @@ class TDTestCase:
         tdSql.query("select sample(c1,100)+2 from ct1")
         tdSql.query("select abs(sample(c1,100)) from ct1")
 
+        # support stable and tbname 
+        tdSql.query("select tbname ,sample(c1,2) from stb1 partition by tbname order by tbname")
+        tdSql.checkRows(4)
+        tdSql.checkData(0,0,'ct1')
+        tdSql.checkData(3,0,'ct4')
+
+        # # bug need fix 
+        # tdSql.query(" select tbname ,c1 ,t1, sample(c1,2) from stb1 partition by tbname order by tbname ")
+        # tdSql.checkRows(4)
+        # tdSql.checkData(0,0,'ct1')
+        # tdSql.checkData(3,0,'ct4')
+        # tdSql.checkData(0,2,1)
+        # tdSql.checkData(3,2,4)
+
+        tdSql.query(" select tbname ,c1 ,t1, sample(c1,2) from stb1 partition by t1 order by t1 ")
+        tdSql.checkRows(4)
+        tdSql.checkData(0,0,'ct1')
+        tdSql.checkData(3,0,'ct4')
+        tdSql.checkData(0,2,1)
+        tdSql.checkData(3,2,4)
+
+        tdSql.query(" select tbname ,c1 ,t1, sample(c1,2) from stb1 partition by c1 order by c1 ")
+        tdSql.checkRows(21)
+
+        # bug need fix 
+        # tdSql.query(" select sample(c1,2) from stb1 partition by c1 ")
+        # tdSql.checkRows(21)
+
+
     def sample_test_run(self) :
         tdLog.printNoPrefix("==========support sample function==========")
         tbnum = 10