Question

我正在连接到DB2数据库，并希望使用PO180M2.PHPPN（PARTNO）的Max（PO180M1.POORDT）或TOP 1分组。我该怎么做？我想我一直在接近但没有让它发挥作用。

SELECT PO180M2.PHPPN AS PartNo, (PO180M2.PHVNPD || ' ' || PO180M2.PHVNP2) AS PartDesc, 
       PO180M1.POORDT AS OrderDate, PO180M2.PHUNCT AS UnitCost
FROM PO180M1, PO180M2 
WHERE PO180M1.POORNO = PO180M2.PHORNO 
ORDER BY PartNo, OrderDate DESC

Answer 1

几乎得到了它。对于任何汇总，Max()，Min()，Avg()，Count()，Sum()，需要GROUP BY子句列出“级别”列通常是指标字段（名称，类别，类型）。

此外，您将省略一个您尝试运行聚合的级别列，此处为POORDT。最后，您将无法ORDER BY聚合的字段，只能列出列出的组字段。

SELECT PO180M2.PHPPN AS PartNo, (PO180M2.PHVNPD || ' ' || PO180M2.PHVNP2) AS PartDesc, 
       PO180M2.PHUNCT AS UnitCost, Max(PO180M1.POORDT) As MaxPOORDT
FROM PO180M1 
INNER JOIN PO180M2 ON PO180M1.POORNO = PO180M2.PHORNO 
GROUP BY PO180M2.PHPPN, (PO180M2.PHVNPD || ' ' || PO180M2.PHVNP2), PO180M2.PHUNCT
ORDER BY PartNo

顺便说一句，我注意到你使用FROM子句中的表连接列表的旧语法和WHERE子句。我将其更改为INNER JOIN ON我相信它符合DB2。

带有join的DB2 SQL SELECT top 1组

1 个答案: