Php 最流行的SQL

我有一个mysql表，其中包含与订单相关的项目

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预期结果：

A=（1+1）2

B=2

C=（2+4）6这个怎么样：

SELECT itemID, SUM(qtyOrdered) AS total FROM testdata GROUP BY itemID ORDER BY total DESC;

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选择itemID，SUM（qtyOrdered）作为blah FROM sqltest GROUP BY itemID ORDER BY blah DESC

应该这样做

这不会给出预期的结果，因为它不是按总金额排序的-它会首先给出单个金额最大的项目，依此类推…给我一个错误：“您的SQL语法有错误”可能是因为count（）为空

SELECT      *
FROM        testdata
ORDER BY    SUM(gtyOrdered) DESC
GROUP BY    itemID

select count(qtyOrdered), qtyOrdered from testdata group by qtyOrdered

SELECT itemID, SUM(qtyOrdered) AS total FROM testdata GROUP BY itemID ORDER BY total DESC;

SELECT      *
FROM        testdata
ORDER BY    SUM(gtyOrdered) DESC
GROUP BY    itemID

SELECT SUM( qtyOrdered ) AS sum_ordered, itemID
FROM testdata
GROUP BY itemID
ORDER BY sum_ordered