sql - 查询以运行每个实例。MS-Access

Answer 1

以下查询应该为您提供所需的内容。它有点长，但它可以解决问题：

`select LIST.Civil_Parish, SD.Site_name, LIST.MSite_Date
from
(
select Civil_Parish, min(Site_date) as MSite_date
from SiteDetail
where Boolean = 1
group by Civil_Parish

union

select Civil_parish, min(Site_date) as MSite_date
from SiteDetail
where Civil_parish not in
(select Civil_parish
from SiteDetail
where Boolean = 1)
group by Civil_Parish) as LIST 
left join sitedetail SD on LIST.Civil_Parish = SD.Civil_Parish and LIST.MSite_Date = SD.Site_Date`

请注意以下事项：

1）我正在使用 PowerUser 的布尔建议。如果布尔列的值为 1，则该行是教区教堂，否则为 0。

2) 为了本示例的目的，我将表“SiteDates”和“SiteDetails”组合在一起，因为它们是 1 比 1。

查询的核心是 A) 在教区中查找最古老的教区教堂，然后 B) 查找没有教区教堂的教区。

A）的代码如下：

'select Civil_Parish, min(Site_date) as MSite_date
from SiteDetail
where Boolean = 1
group by Civil_Parish'

然后，我们将其与没有教区教堂的教区中最古老的教堂联合起来：

'select Civil_parish, min(Site_date) as MSite_date
from SiteDetail
where Civil_parish not in
(select Civil_parish
from SiteDetail
where Boolean = 1)
group by Civil_Parish'

然后，我们将联合查询（此处名为“LIST”）与我们在教区和日期上的原始“SITEDETAIL”表连接起来，以引入教堂名称。