Question

我有一个MS-Access数据库，有两个表我想查询，基本表模式如下所示。我希望了解每个教区最早的教区教堂的细节 - 并且在这个例子中没有教堂里有'教区';我想拉出最早的教堂。

SITEDETAIL：

Site
Reference No. |  Civil Parish |  Site Name         |  NGR East  | NGR North   
1                Assynt          Old Parish Church    6137        3172
2                Assynt          St. Marys            6097        3870
3                Assynt          New Parish Church    6249        3490
4                Bower           Grimbister           2095        4067
5                Bower           St. Andrews          2304        3194
6                Halkirk         Firth Parish Church  7136        3450
7                Holm            Strath Parish Church 4586        2045
8                Holm            St Nicholas Parish   4132        3146

SITEDATES：

Site 
Reference No.  | Date
1                1812
2                1300
3                1900
4                1760
5                1750
6                1838
7                1619
8                1774

我写了一个查询，提取'parish'的所有实例：

SELECT SITEDETAIL.SITEREFNO, SITEDETAIL.CIVPARBUR_CDE, SITEDETAIL.SITENAME, SITEDETAIL.NGRE, SITEDETAIL.NGRN, SITEDATES.DATE

FROM SITEDETAIL INNER JOIN SITEDATES ON SITEDETAIL.SITEREFNO = SITEDATES.SITEREFNO
WHERE (((SITEDETAIL.SITENAME) Like "par*"));

但是，这并没有考虑名称中带有'par *'的多个/没有教堂的实例。

是否可以创建一个贯穿每个民事教区的SQL查询，并选择最早的'教区'或最早的教堂，或者是否有必要编写一个perl脚本来贯穿它们？这可能使用DBI吗？

期望的输出：

Site
Reference No. |  Civil Parish |  Site Name         |  NGR East  | NGR North   | Date
1                Assynt          Old Parish Church    6137        3172          1812
5                Bower           St. Andrews          2304        3194          1750
6                Halkirk         Firth Parish Church  7136        3450          1838
7                Holm            Strath Parish Church 4586        2045          1619

注意：在Assynt的情况下，'Old Parish Church'虽然年纪较大，但因为名字中有“教区”而被选中。

Answer 1

以下查询可以满足您的需求。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，则该行为Parish Church，如果不为，则为0。

2）为了本例的目的，我将表“SiteDates”和“SiteDetails”结合起来，因为它们是1比1。

查询的核心是A）在教区找到最古老的教区教堂，然后B）找到没有教区教堂的巴黎教堂。

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，我们与没有教区教堂的教区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'

然后我们加入联合查询（这里名为“LIST”）和我们在教区和日期的原始“SITEDETAIL”表格，以引入教会名称。

查询以运行每个实例。 MS-访问

1 个答案: