Actian Zen (Pervasive) group_concat

Question

Is there a equivalent function to group_concat in PSQL 15.04? Say I have two tables:

serials:

| serial_number | other_info |
|---------------|------------|
|            s1 |          x |
|            s2 |          x |
|            s3 |          y |
|            s4 |          y |
|            s5 |          z |

orders:

| serial_number | order_number |
|---------------|--------------|
|            s1 |           o3 |
|            s3 |           o2 |
|            s1 |           o1 |
|            s4 |           o4 |

I would like to do something like:

SELECT TOP 3
    serials.serial_number,
    GROUP_CONCAT(orders.order_number ORDER BY orders.order_number ASC)
FROM serials
LEFT JOIN orders on serials.serial_number = orders.serial_number
GROUP BY serials.serial_number

Expected result:

| serial_number | order_number |
|---------------|--------------|
|            s1 |       o1, o3 |
|            s2 |              |
|            s3 |           o2 |