Update index.md

docs/en/14-reference/12-config/index.md

@@ -182,7 +182,7 @@ The parameters described in this document by the effect that they have on the sy
 | Meaning   | count()/hyperloglog() return value or not if the result data is NULL |
 | Vlue Range | 0：Return empty line，1：Return 0       |
 | Default   | 1                            |
-| Notes | When this parameter is setting to 1: for queries containing GROUP BY, PARTITION BY and INTERVAL clause, count/hyperloglog functions do not return value; if count/hyperloglog used together with other aggregate functions, other aggregate functions return NULL. |
+| Notes | When this parameter is setting to 1, for queries containing GROUP BY, PARTITION BY and INTERVAL clause, and input data in certain groups or windows is empty or NULL, the corresponding groups or windows have no return values |
 
 ### maxNumOfDistinctRes