Is it possible to get data of two different rows in one row (postgres)

I have this table whereby the data of the same customer id is in a new row:

order_id | cust_id | order_date                 | menu_item 
------------------------------------------------------------
order1   | cust1   | January 19, 2020, 1:00 PM  |           
         | cust1   |                            | food_A    

Is it possible to get a one row of the data like below:

order_id | cust_id | order_date                 | menu_item 
------------------------------------------------------------
order1   | cust1   | January 19, 2020, 1:00 PM  | food_A       

I tried joining but then i get the same as the table where it prints out two data instead of one. Might be my join isn’t correct. Appreciate the help. thanks

select s.cust_id, s.menu_item from tableA s inner join tableA t on s.cust_id = t.cust_id

Answer

In your case, assuming the missing values be NULL, you may just aggregate by order_id and cust_id and then take the max of the other two columns:

SELECT
    order_id,
    cust_id,
    MAX(order_date) AS order_date,
    MAX(menu_item)  AS menu_item
FROM tableA
GROUP BY
    order_id,
    cust_id;