> ## Documentation Index
> Fetch the complete documentation index at: https://docs.risingwave.com/llms.txt
> Use this file to discover all available pages before exploring further.

# WITH ORDINALITY clause

> The `WITH ORDINALITY` clause can be used with set functions in the `FROM` clause of a query.

An additional integer column will be added to the table, which numbers the rows returned by the function, starting from 1. By default, the generated column is named `ordinality`.

See [Set-returning functions](/sql/functions/set-returning) for a list of supported set functions.

Here is a simple example of how the `WITH ORDINALITY` clause works.

```sql theme={null}
SELECT * FROM unnest(array[0,1,2]) WITH ORDINALITY;
```

The output will be as follows.

```sql theme={null}
 unnest | ordinality
--------+------------
      0 |          1
      1 |          2
      2 |          3
```

If we have a table `t` like so:

```sql theme={null}
   arr
---------
 {a,b,c}
 {d,e}
```

We can use the `unnest` function on the column `arr`, call `WITH ORDINALITY`, and rename the newly generated columns.

```sql theme={null}
SELECT * FROM t CROSS JOIN unnest(t.arr) WITH ORDINALITY AS x(elts, num);
```

The results will be as follows.

```sql theme={null}
   arr   | elts | num
---------+------+-----
 {a,b,c} | c    |   3
 {a,b,c} | b    |   2
 {a,b,c} | a    |   1
 {d,e}   | e    |   2
 {d,e}   | d    |   1
```