将具有1到N关系的表组合成1行记录和N记录的最后一个值

Question

我需要修改我之前的帖子 如何将具有1对多关系的表组合成1行记录

how to combine tables with 1 to many relationship into 1 line of record

现在我的问题是我的记录现在有1对多的关系。我需要展示的只是最后一条记录，并将其合并为一行 表tbl_equipment和tbl_warranty

这是所需的输出

这是我正在尝试实施的代码

 SELECT
 a.equipmentid,
 a.codename,
 a.name,
 a.labelid,
 a.ACQUISITIONDATE,
 a.description,
 a.partofid,
 w1.warrantyid as serviceidwarranty,
 w1.startdate,
 w1.enddate,
 w2.warrantyid as productidwarranty,
 w2.startdate,
 w2.enddate,
 s.equipstatusid,
 l.equiplocationid FROM TBL_EQUIPMENTMST a
 left JOIN tbl_equipwarranty w1
 ON w1.equipmentid=a.equipmentid and w1.serviceproduct = 'service'
 left JOIN tbl_equipwarranty w2
 ON w2.equipmentid=a.equipmentid and w2.serviceproduct = 'product'
 left join tbl_equipstatus s
 on a.equipmentid = s.equipmentid
 left join tbl_equiplocation l
 on a.equipmentid = l.equipmentid  WHERE a.equipmentid = '112'

我只想在输出中显示保修产品和保修服务的最后一个值的1条记录。任何人都可以指导我如何修改我的代码，以便当我尝试加入上面列出的所有表时，只能将最后一个保修记录作为输出产生1条记录。 我使用firebird作为数据库。如果你在mysql中有一个解决方案，请告诉我，并试着找到firebird中的对应物。

Answer 1

with summary as(
select e.equipmentid ,e.Codename,e.Name,w.warrantyid ,w.Satartdate ,w.Enddate,w.warrantytype 
from Eqp e
join Warranty w
on(w.equipmentid =e.equipmentid )
where w.warrantyid =3)

select *,w.warrantyid,w.Satartdate ,w.Enddate,w.warrantytype
from summary s
join  Warranty w
on s.Satartdate =w.Satartdate and s.Enddate =w.Enddate 
where w.warrantyid =4

Answer 2

在阅读了Barmar关于解决问题的评论之后。我想出子查询可以解决我的问题。子查询对我来说是个新词。我研究如何使用子查询，并在下面提出了一个解决方案。如果我的代码错误或如何提高查询性能，你可以纠正我

SELECT 
    a.equipmentid,a.codename,a.name,a.labelid,a.ACQUISITIONDATE,a.description,a.partofid,
    w1.warrantyid as serviceidwarranty,w1.startdate,w1.enddate,
    w2.warrantyid as productidwarranty,w2.startdate,w2.enddate,
    s.equipstatusid,
    l.equiplocationid 
FROM 
    TBL_EQUIPMENTMST a
left JOIN
    (select first 1 *
     from tbl_equipwarranty 
     where equipmentid='112' and serviceproduct = 'service'
     order by warrantyid desc) w1 ON w1.equipmentid = a.equipmentid 
                                     and w1.serviceproduct = 'service'
left JOIN
    (select first 1 *
     from tbl_equipwarranty 
     where equipmentid = '112' and serviceproduct = 'product'
     order by warrantyid desc) w2 ON w2.equipmentid = a.equipmentid 
                                     and w2.serviceproduct = 'product'
left join
    (select first 1 *
     from tbl_equipstatus 
     where equipmentid = '112'
     order by equipstatusid desc) s on a.equipmentid = s.equipmentid
left join
    (select first 1 *
     from tbl_equiplocation 
     where equipmentid = '112'
     order by equiplocationid desc) l on a.equipmentid = l.equipmentid  
WHERE 
     a.equipmentid = '112'