20
3.
相關的
SQL
語法
(10/10)
Group
運算式
(
1
)
找出至少購買五次以上的顧客其平均消費金
額
SQL
:
SELECT avg(p_Price) AS avgprice
FROM order
GROUP BY pId
HAVING count(*) >= 5
XML
:
FOR $op IN distinct(document("order.xml")//pId)
LET $o := document("customer1")//order_record[pId = $op]
WHERE count($o) >=5
RETURN
<customer1>
$op,
<avgprice> avg($o/price) </avgprice>
</ customer1>