PostgreSQL SQL Error [42703]: ERROR: column 'minute' does not exist

Question

I have the below query and I am getting the following error:

SQL Error [42703]: ERROR: column 'minute' does not exist

However I am not referencing any field called minute .

SELECT customer_id,
MAX(created_at) last_order_date,
MAX(created_at) + ((SELECT EXTRACT(MINUTE FROM MAX(created_at)-MIN(created_at)) 
FROM (SELECT customer_id, created_at
FROM (SELECT customer_id, created_at, rank() over (partition by customer_id order by created_at desc) lasttwo
FROM orders) sub
WHERE sub.lasttwo <= 2
AND SUM(DATEDIFF(MINUTE,MIN(created_at),MAX(created_at))) > 2) s2) ::text||' minute')::INTERVAL AS nextdate,
(SELECT AVG(total_price - total_tax) 
FROM (SELECT customer_id, created_at, total_price, total_tax
FROM (SELECT customer_id, created_at, total_price, total_tax, rank() over (partition by customer_id order by created_at desc) lasttwo
FROM orders) sub
WHERE sub.lasttwo <= 2
AND SUM(DATEDIFF(MINUTE,MIN(created_at),MAX(created_at))) > 2) s2) nextval 
FROM orders 
GROUP BY customer_id

Answer 1

Needed to use EXTRACT rather than DATEDIFF

SELECT customer_id,
MAX(created_at) last_order_date,
MAX(created_at) + ((SELECT EXTRACT(MINUTE FROM MAX(created_at)-MIN(created_at)) 
FROM (SELECT customer_id, created_at
FROM (SELECT customer_id, created_at, rank() over (partition by customer_id order by created_at desc) lasttwo
FROM orders) sub
WHERE sub.lasttwo <= 2
AND SUM(EXTRACT(MINUTE FROM MAX(created_at)-MIN(created_at))) > 2) s2) ::text||' minute')::INTERVAL AS nextdate,
(SELECT AVG(total_price - total_tax) 
FROM (SELECT customer_id, created_at, total_price, total_tax
FROM (SELECT customer_id, created_at, total_price, total_tax, rank() over (partition by customer_id order by created_at desc) lasttwo
FROM orders) sub
WHERE sub.lasttwo <= 2
AND SUM(EXTRACT(MINUTE FROM MAX(created_at)-MIN(created_at))) > 2) s2) nextval  
FROM orders 
GROUP BY customer_id