加入三张桌子 - Mysq-l内外连接也许？

Question

我正在努力让这个查询起作用。我有三个表，我想进行查询以获得红色区域。 每个圆圈都是一个结构不同的表格。我已经管理了很多内部联接的组合，但我特别想要得到所有的红色区域。

付款：idPayment，idInvoice，金额，日期。

B发票：idInvoice，金额日期。

C PromissoryNotes：IdNote，idInvoice，amount，date。

到目前为止......

SELECT B.idInvoice，A.idPayment，C.idNote FROM（发票b INNER JOIN付款a a a.idInvoice = b.idInvoice）LEFT OUTER JOIN PromissoryNotes c ON c.idInvoice = b.idInvoice ORDER BY idInvoice。< / p>

DOESNT QUITE WORK

有什么建议吗？

Answer 1

你非常接近 - 另一个OUTER JOIN和一些WHERE标准可以解决问题：

SELECT B.idInvoice, A.idPayment, C.idNote 
FROM Invoice b 
    LEFT JOIN payments a ON a.idInvoice=b.idInvoice
    LEFT JOIN PromissoryNotes c ON c.idInvoice=b.idInvoice 
WHERE a.idInvoice IS NOT NULL 
    OR c.idInvoice IS NOT NULL
ORDER BY B.idInvoice

这基本上说的是给我表B中的所有结果，其中表a或表c中有匹配。

• Condensed SQL Fiddle Demo

Answer 2

你可以这两种方式：

1）创建一个集合A，它是B和A的内部联接，创建一个集合C，它是B和C的内部集合，然后是集合A和C.

2）创建一个内部连接A和B的子查询，然后完全外部连接到内部连接C和B的子查询。

1）的例子

SELECT  b.idInvoice FROM Invoice B 
JOIN Payments A on A.IdInvoice = B.IdInvoice
UNION 
SELECT  b.idInvoice FROM Invoice B 
JOIN PromissoryNotes C on c.idInvoice = B.id Invoice

2）的例子

SELECT idInvoice FROM 
    ( 
        SELECT  b.idInvoice FROM Invoice B 
        JOIN Payments A on A.IdInvoice = B.IdInvoice
    ) B FULL OUTER JOIN 
    (
        SELECT  b.idInvoice FROM Invoice B 
        JOIN Payments A on A.IdInvoice = B.IdInvoice
    ) C on b.idInvoice = C.idInvoice 

Answer 3

尝试

SELECT B.idInvoice, A.idPayment, C.idNote FROM Invoice B INNER JOIN payments A ON        A.idInVoice = B.idInvoice INNER JOIN PromissoryNotes C ON C.idInvoice = B.idInvoice ORDER BY idInvoice

INNER JOIN表示您获得两个表的交集。所以这就是你想要的。

Answer 4

这可以解决这个问题吗？

SELECT 
ZZ.idInvoice,
ZZ.idPayment,
YY.idInvoice,
YY.idNote 
FROM
(SELECT idInvoice, idPayment
    FROM Invoice b 
        INNER JOIN payments a ON a.idInvoice=b.idInvoice) AS ZZ
FULL OUTER JOIN
(SELECT idInvoice, idNote
    FROM PromissoryNotes c 
        INNER JOIN payments a ON a.idInvoice=c.idInvoice) AS YY ON ZZ.idInvoice = YY.idInvoice

Answer 5

SELECT p.idInvoice, p.idPayment, idNote 
FROM Payments p JOIN Invoice i ON p.adInvoice-i.adInvoice RIGHT OUTER JOIN PromissoryNotes
UNION
SELECT i.idInvoice, idPayment, idNote 
FROM Invoice i JOIN PromissoryNotes pn ON i.idInvoice=pn.idInvoice RIGHT OUTER JOIN Payments

您需要包含外部联接，因为要联合的结果表必须具有相同的架构。我相信这些是查询中需要的字段。