Problems Linking the max value of an attribute in a table to its primary Key
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15-01-2021 - |
题
I need to extract the order_id with the max number of items, I've figured out how to extract the max value but I'm having problems linking it to the particular order_id.
PS: I'm a uni student so please go easy on me.
select MAX(f), x.order_id
from ( select count( distinct z.item_id) f, z.order_id as g
from Order_item z, Item i, Ordert o
where o.order_id=z.order_id
group by z.order_id
) AS T, Ordert x
having x.order_id=g;
解决方案
Maybe you need simple
select count( distinct z.item_id) f, z.order_id as g
from Order_item z, /* Item i, */ Ordert o
where o.order_id=z.order_id
group by z.order_id
order by f desc limit 1
?
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