如何使用 SQL select 的结果来获取另一个表中的记录？

Question

I'm having a hard time with creating a Sql that pull data from three tables.

Here are part of the structure of each table:

Customer table:
accnum   integer
name     string
address  string
Routeno  string
delno    integer

Invoice table:
accnum   integer
invnum   string
deldate  date
amount   float
routeno  string
vstatus  string

Card table:
accnum    integer
expdate   string

The result I need is all the customer that is on routeno 1, 2 and 3 then I need any invoices that have the delivery date (deldate) and the expdate of any that have a credit card on file. Sorted by delno.

Select c.accnum, c.name, c.address, c.routeno, c.delno from customer c
where c.routeno in ('1','2','3')

From this result I need the following.

Select i.invnum, i amount from invoice i
where i.deldate = '2020-05-27' and (vstatus <> 'V' or vstatus is null)
and i.accnum=c.accnum
and i.routeno in ('1','2','3')

Select e.expdate from Card
where e.accnum=c.accnum

I tried using Join, but then I only get the customer that have invoices I nned them all.

Select c.accnum, c.name, c.address, c.routeno, i.invnum, i.amount,  e.expdate from Customer c
left Join Card e on c.accnum=e.accnum 
left Join Invoice i on c.accnum=i.accnum
where i.deldate = '2020-05-27' and (vstatus <> 'V' or vstatus is null)
and i.accnum=c.accnum
and i.routeno in ('1','2','3')
order by c.routeno, c.delno

I need a result like this:

accnum name      address    routeno  delno invnum amount expdate
000030 Smith     1 main st   1         1   A123    5.00   12/22
000030 Smith     1 main st   1         1   A125    8.00   12/22
000022 Knox      14 main st  1         2   A124    10.00   
000014 Vohs      20 main st  1         3   A119    4.00   11/21
000078 Bow       3 Camp Ave  1         4   A120    3.00
000015 Jordan    4 River rd  2         1   A118    11.00  10/23
000015 Jordan    4 River rd  2         1   A117    15.00  10/23

Thanks for any help. KHJ

Answer 1

The link philipxy provided should point you the right direction. Another way approach this is to create an outer joined subquery with the desired filter criteria on invoice.

  SELECT c.accnum,
         c.name,
         c.address,
         c.routeno,
         i.invnum,
         i.amount,
         e.expdate
    FROM Customer c
         LEFT JOIN Card e ON c.accnum = e.accnum
         LEFT JOIN
         (SELECT accnum, invnum, amount
            FROM Invoice
           WHERE     deldate = '2020-05-27'
                 AND (vstatus <> 'V' OR vstatus IS NULL)
                 AND routeno IN ('1', '2', '3')) i
             ON i.accnum = c.accnum
ORDER BY c.routeno, c.delno