Sub-queries and aliases cannot be used in Mysql,update

Update Po_header

Set Total_fee = (
Select Ip.payment-ip.post_fee
From Po_header IP
where ip.po_header_id = po_header_id
)
where trade_id in (
Select trade_id from trade where shop_id = 2094;

The above update script needs to be done in MySQL by Innerjoin

Update Po_header p1 INNER JOIN
(select po_header_id, (payment-post_fee) Total_fee
From Po_header) IP on
ip.po_header_id = p1.po_header_id
Set P1.total_fee = Ip.total_fee
where trade_id in (
Select trade_id from trade where shop_id = 2094
)

Sub-queries and aliases cannot be used in Mysql,update