Question

我正在尝试编写一个查询，从日期比指定日期更新的给定listNumber中为每companyId提取searchId的最低数量。因此，对于每个公司，我会得到一行，其中包含该公司所有条目中listNumber的最低companyId行的数据。

（简化的）MySQL表是这样的：

id          (PK) 
companyId   (int) 
searchId    (int) 
productName (varchar) 
effective   (decimal) 
listNumber  (int) 
addedWhen   (timestamp)

searchId和SELECT MIN(listNumber) AS listnumber, bankId, productName, effective FROM DummyTableName WHERE addedWhen >= '2011-04-05 00:00:00' AND searchId='26' GROUP BY companyId与其他两个表格的PK相关联。

我尝试过像

这样的东西

listNumber

但没有运气，因为这将返回最低companyId，但所有其他数据将从具有相同{{1}}的另一行中获取。

关于如何正确获取此查询的任何想法？

Answer 1

SELECT t1.* FROM table t1 
  JOIN (SELECT companyId, MIN(listNumber) min_listNumber FROM table
    WHERE addedWhen >= '2011-04-05 00:00:00' AND searchId='26'
    GROUP BY companyId) t2
  ON t1.companyId = t2.companyId AND t1.listnumber = t2.min_listnumber
WHERE t1.addedWhen >= '2011-04-05 00:00:00' AND t1.searchId='26';

Answer 2

... HAVING Something = MIN(Something)

Answer 3

你可以尝试

select listnumber,bankid,productname, effective 
from dummytablename
left join (SELECT MIN(listNumber) AS listnumber, bankId 
FROM DummyTableName 
WHERE addedWhen >= '2011-04-05 00:00:00' 
AND searchId='26' group by bankid) as t where dummytablename.listnumber=t.listnumber and dummytablename.bankid=t.bankid

但它有点难看（我确定我使用了比这更好的解决方案）

Answer 4

如果除了聚合函数字段以外的所有内容进行分组，它应该可以工作。在这种情况下，如果你得到一个字段的计数或总和并希望显示该计数/总和，你应该只需要HAVING。

SELECT MIN(listNumber) AS listnumber, bankId, productName, effective 
FROM DummyTableName 
WHERE addedWhen >= '2011-04-05 00:00:00' 
AND searchId='26' 
GROUP BY bankId, productName, effective

MySQL查询从指定的另一行中提取数据

4 个答案: