Question

我有以下SQL查询：

SELECT porel.refcode, podetail.ponum, SUM(podetail.orderqty * podetail.unitcost) AS Total
FROM podetail
LEFT JOIN porel ON podetail.ponum = porel.ponum
WHERE porel.poline=podetail.poline AND porel.reftype = 'SPEX'
GROUP BY porel.refcode, podetail.ponum
ORDER BY porel.refcode, podetail.ponum

可以很好地为我提供ponums的列表及其对refcodes的总价值。

我现在要添加第三列vendor.name。 vendor表有一个字段vendorid，它与podetail表共享。

有多个podetail条记录具有相同的ponum，但这些记录也会匹配vendorid。

有人可以建议我如何在vendor.name字段中添加而不返回额外的行吗？

Answer 1

将其添加到GROUP BY。我假设每个podetail.ponum都会有一个供应商。顺便说一下，由于Where子句中的porel.reftype = 'SPEX'，当前查询将左连接转换为内连接。

SELECT   porel.refcode,
         podetail.ponum,
         SUM(podetail.orderqty * podetail.unitcost) AS Total,
         vendor.name
FROM     podetail
         INNER JOIN vendor ON podetail.vendorid = vendor.vendorid
         LEFT JOIN porel ON podetail.ponum = porel.ponum
WHERE    porel.poline=podetail.poline
AND      porel.reftype = 'SPEX'
GROUP BY porel.refcode,
         podetail.ponum,
         vendor.name
ORDER BY porel.refcode,
         podetail.ponum

Answer 2

Heya，Rogue。我想说的不仅仅是评论，所以在这里。

另一个更容易诊断的问题是：

SELECT
    porel.refcode,
    podetail.ponum,
    SUM(podetail.orderqty * podetail.unitcost) AS Total,
    podetail.vendorid
FROM
    podetail
    LEFT JOIN porel
    ON podetail.ponum = porel.ponum
WHERE
    porel.poline = podetail.poline 
    AND porel.reftype = 'SPEX' 
GROUP BY
    porel.refcode, 
    podetail.ponum,
    podetail.vendorid
ORDER BY
    refcode, 
    ponum

在这里，我们根本没有加入vendor，完全不在等式中。相反，我们只需汇总podetail.vendorid。

您可以发布此查询的输出吗？

Answer 3

SELECT   porel.refcode,
         podetail.poline,
         podetail.ponum,
         SUM(podetail.orderqty * podetail.unitcost) AS Total,
         vendor.name
FROM     podetail
         INNER JOIN vendor ON podetail.vendorid = vendor.vendorid
         LEFT JOIN porel ON podetail.ponum = porel.ponum
WHERE    porel.poline=podetail.poline
AND      porel.reftype = 'SPEX'
GROUP BY porel.refcode,
         podetail.ponum,
         vendor.name
ORDER BY porel.refcode,
         podetail.poline,
         podetail.ponum

我认为，您无需在podetail.poline和SELECT中加入GROUP BY。

Answer 4

由于您正在聚合podetails，只需汇总供应商名称：

SELECT porel.refcode, podetail.ponum
, MAX(vendor.name) as VendorName
, SUM(podetail.orderqty * podetail.unitcost) AS Total
FROM podetail
LEFT JOIN vendor on podetail.vendorid = vendor.vendorid
LEFT JOIN porel ON podetail.ponum = porel.ponum
WHERE porel.poline=podetail.poline AND porel.reftype = 'SPEX'
GROUP BY porel.refcode, podetail.ponum
ORDER BY porel.refcode, podetail.ponum

如果您愿意，可以使用MIN（）。

如何在包含SUM的SQL查询中添加第三个表

4 个答案: