Document the enable_positional_arguments setting

docs/en/operations/settings/settings.md

@@ -3749,3 +3749,39 @@ Exception: Total regexp lengths too large.
 **See Also**
 
 -   [max_hyperscan_regexp_length](#max-hyperscan-regexp-length)
+
+## enable_positional_arguments {#enable-positional-arguments}
+
+Enables or disables supporting positional arguments for [GROUP BY](../../sql-reference/statements/select/group-by.md), [LIMIT BY](../../sql-reference/statements/select/limit-by.md), [ORDER BY](../../sql-reference/statements/select/order-by.md) statement. When you want to use column numbers instead of titles in these clauses, set `enable_positional_arguments = 1`.
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: `0`.
+
+**Example**
+
+Query:
+
+```sql
+CREATE TABLE positional_arguments(one Int, two Int, tree Int) ENGINE=Memory();
+
+INSERT INTO positional_arguments VALUES (10, 20, 30), (20, 30, 10), (30, 10, 20);
+
+SET enable_positional_arguments = 1;
+
+SELECT * FROM positional_arguments ORDER BY 2,3;
+```
+
+Result:
+
+```text
+┌─one─┬─two─┬─tree─┐
+│  30 │  10 │   20 │
+│  10 │  20 │   30 │
+│  20 │  30 │   10 │
+└─────┴─────┴──────┘
+
+```

docs/en/sql-reference/statements/select/index.md

@@ -144,7 +144,7 @@ Extreme values are calculated for rows before `LIMIT`, but after `LIMIT BY`. How
 
 You can use synonyms (`AS` aliases) in any part of a query.
 
-The `GROUP BY` and `ORDER BY` clauses do not support positional arguments. This contradicts MySQL, but conforms to standard SQL. For example, `GROUP BY 1, 2` will be interpreted as grouping by constants (i.e. aggregation of all rows into one).
+The `GROUP BY`, `ORDER BY` and `LIMIT BY` clauses support positional arguments. For example, ORDER BY 1,2 will be sorting rows on the table on the first and then the second column.
 
 ## Implementation Details {#implementation-details}