test: add test case for max/min function

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

@@ -45,6 +45,22 @@ class TDTestCase:
         tdSql.query(f"select max(col1) from {dbname}.stb where col2<=5")
         tdSql.checkData(0,0,5)
 
+        tdSql.query(f"select ts, max(col1) from {dbname}.stb")
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 1, np.max(intData))
+
+        tdSql.query(f"select ts, max(col1) from {dbname}.stb_1")
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 1, np.max(intData))
+
+        tdSql.query(f"select ts, min(col9) from {dbname}.stb")
+        tdSql.checkRows(1)        
+        tdSql.checkData(0, 1, np.min(floatData))
+
+        tdSql.query(f"select ts, min(col9) from {dbname}.stb_1")
+        tdSql.checkRows(1)        
+        tdSql.checkData(0, 1, np.min(floatData))
+
     def max_check_ntb_base(self, dbname="db"):
         tdSql.prepare()
         intData = []