Question

我用子查询编写了一个查询，它们都有一个顺序。我有一个奇怪的行为，有时我没有回到所有行，有时我有0行，但如果我运行内部查询我总是有正确的行。子查询有一些限制吗？ MySql是版本5.5

非常感谢

SELECT
*
FROM
(
    SELECT
        @fakeId := @fakeId + 1 AS fakeId,
        @balance := (@balance +  traIn.amount) AS balance,

    FROM
        (SELECT @fakeId := 0, @balance := 0) AS vars,
        table1 traIn
    INNER JOIN table2 traTypeIn ON traIn._id = traTypeIn.id
    INNER JOIN table3 ptfIn ON traIn.ptf_id = ptfIn.id
    LEFT JOIN `user` u ON u.id = traIn.user_create_id
    LEFT JOIN `user` up ON up.id = traIn.user_update_id

    WHERE
    <---  a couple of constraints -->
    ORDER BY
        traIn.date
) AS data
    ORDER BY data.fakeId DESC
    LIMIT 50;

Answer 1

为什么不在子查询中选择traIn.date，之后只选择fakeId，balance 这样的事情：

SELECT
data.fakeId, data.balance
FROM
(
    SELECT
        @fakeId := @fakeId + 1 AS fakeId,
        @balance := (@balance +  traIn.amount) AS balance,
        traIn.date as date1
    FROM
        (SELECT @fakeId := 0, @balance := 0) AS vars,
        table1 traIn
    INNER JOIN table2 traTypeIn ON traIn._id = traTypeIn.id
    INNER JOIN table3 ptfIn ON traIn.ptf_id = ptfIn.id
    LEFT JOIN `user` u ON u.id = traIn.user_create_id
    LEFT JOIN `user` up ON up.id = traIn.user_update_id

    WHERE
    <---  a couple of constraints -->
) AS data
    ORDER BY data.date1, data.fakeId DESC
    LIMIT 50;

子查询与订单

1 个答案: