Question

我是一个初学者，我对此事有基本的了解，因此，如果我找不到正确的答案，我会打个招呼。这是我编写的代码。它返回的正是我所需要的，但是我觉得这不是一个很好的解决方案，有什么建议吗？我正在使用Oracle SQL Developer。预先感谢

SELECT
    ta.id,
    tb.taid,
    tc.idb,
    ta.durata,
    tc.durata,
    tb.durata,
    ta.data_attivazione,
    ta.data_disattivazione,
    tc.data_inizio,
    tc.data_fine,
    tb.data_inizio,
    tb.data_fine
FROM
    tableA ta
    tableB ta
    tableC tc
WHERE
    ta.id = 3456
    AND tb.taid = 3456
    AND tc.idb = 3456
    OR (
        ta.id = 3457
        AND tb.taid = 3457
        AND tc.idb = 3457
    )

Answer 1

使用正确，明确，标准 JOIN语法：

select . . .
from tableA ta join
     tableB tb
     on ta.id = tb.taid join
     tableC tc
     on tc.idb = ta.id
where ta.id in (3456, 3457)

Answer 2

使用join：

SELECT
    ta.id,
    tb.taid,
    tc.idb,
    ta.durata,
    tc.durata,
    tb.durata,
    ta.data_attivazione,
    ta.data_disattivazione,
    tc.data_inizio,
    tc.data_fine,
    tb.data_inizio,
    tb.data_fine
FROM
    tableA ta join tableB tb on ta.id= tb.taid
    join tableC tc on tb.taid = tc.idb
WHERE
    ta.id in (3456, 3457)

Answer 3

您可以使用联接来简化代码：

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SQL-WHERE AND / OR子句的替代方法

3 个答案: