如果子查询没有找到联结，如何忽略WHERE IN子句？

我从表中使用以下查询选择交易：如果子查询没有找到联结，如何忽略WHERE IN子句？

SELECT t.* 
FROM transactions AS t 
WHERE t.id IN 
(
    SELECT t2.id 
    FROM `virtual_account-account` AS vaa 
    LEFT JOIN transactions AS t2 
    ON t2.account = vaa.account 
    WHERE vaa.virtual_account = 3 
) 
AND t.id IN 
(
    SELECT tt.transaction 
    FROM `virtual_account-tag` AS vat 
    LEFT JOIN `transaction-tag` AS tt 
    ON tt.tag = vat.tag 
    WHERE vat.virtual_account = 3 
) 
ORDER BY t.date

不过，我想修改该这样，如果，例如，结合表virtual_account-account不包含任何路口，其中vaa.virtual_account = 3，然后应该忽略相应的t.id IN (...)条件。到目前为止，我没有找到解决方案，所以任何帮助将不胜感激。

来源

2013-07-27 Niko

怎么样，如果两个子选择返回任何结果？你想显示所有交易还是仅显示所有交易？ –

@FabianBigler其实，我不太在意这种情况，因为这是不可能发生的。然而，空的结果会比选择所有交易更好。 – Niko

只是一个或两个条件之间：

SELECT t.* 
FROM transactions AS t 
WHERE t.id IN 
(
    SELECT t2.id 
    FROM `virtual_account-account` AS vaa 
    LEFT JOIN transactions AS t2 
    ON t2.account = vaa.account 
    WHERE vaa.virtual_account = 3 
) 
OR t.id IN 
(
    SELECT tt.transaction 
    FROM `virtual_account-tag` AS vat 
    LEFT JOIN `transaction-tag` AS tt 
    ON tt.tag = vat.tag 
    WHERE vat.virtual_account = 3 
) 
ORDER BY t.date

如果一个人没有返回，它仍然会返回其他交易。

来源

2013-07-27 11:57:25

他说它应该被忽略 –

感谢您的回应，但不幸的是，并非如此简单：如果在ID为3的两个联结表（虚拟账户 - 账户或虚拟账户 - 标签）都有条目，那么应该有AND条件。 – Niko

以下方法将子查询转换为联接并使用变量来计算子查询中的行数。该where条款然后使用这个变量为你想要的逻辑：

SELECT t.* 
FROM transactions t left outer join 
    (SELECT t2.id, @cnt := @cnt + 1 
     FROM `virtual_account-account` AS vaa 
      LEFT JOIN transactions AS t2 
      ON t2.account = vaa.account cross join 
      (select @cnt := 0) 
     WHERE vaa.virtual_account = 3 
     group by t2.id 
    ) c1 
    on c1.id = t.id 
WHERE (c1.id is not null or @cnt = 0) and 
     t.id IN (SELECT tt.transaction 
       FROM `virtual_account-tag` AS vat 
        LEFT JOIN `transaction-tag` AS tt 
        ON tt.tag = vat.tag 
       WHERE vat.virtual_account = 3 
    ) 
ORDER BY t.date;

注意，子查询消除重复（使用group by）。否则，您可能会遇到导致多行的多个匹配问题。

来源

2013-07-27 12:00:22

有点笨拙和冗长，但是......

SELECT t.* 
FROM transactions AS t 
WHERE t.id IN 
(
    SELECT t2.id 
    FROM `virtual_account-account` AS vaa 
    LEFT JOIN transactions AS t2 
    ON t2.account = vaa.account 
    WHERE vaa.virtual_account = 3 
) 
AND t.id IN 
(
    SELECT tt.transaction 
    FROM `virtual_account-tag` AS vat 
    LEFT JOIN `transaction-tag` AS tt 
    ON tt.tag = vat.tag 
    WHERE vat.virtual_account = 3 
    AND EXISTS 
    (
     SELECT t2.id 
     FROM `virtual_account-account` AS vaa 
     LEFT JOIN transactions AS t2 
     ON t2.account = vaa.account 
     WHERE vaa.virtual_account = 3 
    ) 
) 
ORDER BY t.date

来源

2013-07-27 12:05:09 asantaballa

尝试：

SELECT t.* 
FROM (select count(*) vaa 
     FROM `virtual_account-account` 
     WHERE virtual_account = 3) a 
CROSS JOIN (select count(*) vat 
      FROM `virtual_account-tag` 
      WHERE virtual_account = 3) g 
CROSS JOIN transactions AS t 
LEFT JOIN `virtual_account-account` vaa 
     ON t.id = vaa.id AND vaa.virtual_account = 3 
LEFT JOIN `virtual_account-tag` vat 
    JOIN `transaction-tag` tt ON tt.tag = vat.tag 
     ON t.id = tt.transaction AND vat.virtual_account = 3 
WHERE (a.vaa = 0 OR vaa.id IS NOT NULL) AND 
     (g.vat = 0 OR vat.tag IS NOT NULL) 
GROUP BY t.id 
ORDER BY t.date

来源

2013-07-27 12:06:58

如果子查询没有找到联结，如何忽略WHERE IN子句？

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