removed from functions

Author: ashwinkumar12345

docs/sql/functions.md

@@ -131,54 +131,3 @@ Function | Specification | Example
 if | `if(boolean, es_type, es_type) -> es_type` | `SELECT if(false, 0, 1) FROM my-index LIMIT 1`, `SELECT if(true, 0, 1) FROM my-index LIMIT 1`
 ifnull | `ifnull(es_type, es_type) -> es_type` | `SELECT ifnull('hello', 1) FROM my-index LIMIT 1`, `SELECT ifnull(null, 1) FROM my-index LIMIT 1`
 isnull | `isnull(es_type) -> integer` | `SELECT isnull(null) FROM my-index LIMIT 1`, `SELECT isnull(1) FROM my-index LIMIT 1`
-
-## Ranking
-
-Ranking functions assign an incremental rank to each row in the frame.
-
-If the ranking function is not used with the window definition that defines the order of data rows, the result is undetermined.
-
-### ROW_NUMBER
-
-`ROW_NUMBER` assigns a row number to data rows in a random order. As a special case, the row number is always increased by 1 regardless of the fields specified in the `ORDER BY` list.
-
-```sql
-od> SELECT gender, balance, ROW_NUMBER() OVER(PARTITION BY gender ORDER BY balance) AS num FROM accounts;
-```
-
-| gender | balance | num
-:--- | :---
-| F        | 32838     | 1     
-| M        | 4180      | 1     
-| M        | 5686      | 2     
-| M        | 39225     | 3     
-
-### RANK
-
-The `RANK` function assigns a rank to each row. For rows that have the same values for fields specified in the `ORDER BY` list, the same rank is assigned. If this is the case, the next few ranks is skipped depending on the number of ties.
-
-```sql
-od> SELECT gender, RANK() OVER(ORDER BY gender DESC) AS rnk FROM accounts;
-```
-
-| gender | rank
-:--- | :---
-| M        | 1     
-| M        | 1     
-| M        | 1     
-| F        | 4     
-
-### DENSE_RANK
-
-Similar to the `RANK` function, `DENSE_RANK` also assigns a rank to each row. The difference is there is no gap between the ranks.
-
-```sql
-SELECT gender, DENSE_RANK() OVER(ORDER BY gender DESC) AS rnk FROM accounts;
-```
-
-| gender | rank
-:--- | :---
-| M        | 1     
-| M        | 1     
-| M        | 1     
-| F        | 2