我正在开发一个PHP接口,以显示来自两个不同数据库的一些结果:一个MySQL数据库(.sql)和一个Access数据库(.mdb)。当我查询结果时,我让用户选择他要列出的结果数,这样我就可以通过一些PHP乐趣来限制和分页它们。
这对于MySQL DB来说是完美无缺的,其中LIMIT子句以简洁的方式完成所有工作。 Access DB的说法不同:Access没有LIMIT子句,因此我必须使用TOP子句。太糟糕了,这使分页变得很痛苦。
我在接受的this question答案中找到了一个很好的例子,但是我遇到了问题。首先,让我向您展示一些摘要查询:

查询#1

SELECT TOP 5 *
FROM `Table_1` INNER JOIN `Table_2`
ON `Table_1`.`Some_ID` = `Table_2`.`Some_ID`
AND `Table_1`.`Timestamp` = `Table_2`.`Timestamp`
WHERE `Table_1`.`Some_ID` LIKE 'ID %' AND `Table_1`.`Timestamp` LIKE '2018/03/20 %';


查询#2

SELECT TOP 5 *
FROM `Table_1` INNER JOIN `Table_2`
ON `Table_1`.`Some_ID` = `Table_2`.`Some_ID`
AND `Table_1`.`Timestamp` = `Table_2`.`Timestamp`
WHERE `Table_1`.`Some_ID` LIKE 'ID %' AND `Table_1`.`Timestamp` LIKE '2018/03/20 %'
ORDER BY `Table_1`.`Some_ID`;


根据要求,查询1仅显示前5个结果。
遗憾的是,当我添加ORDER BY子句时,查询2将所有满足我条件的结果返回给我。

像这样的MySQL查询不会发生相同的事情:

查询#3

SELECT *
FROM `Table_1` INNER JOIN `Table_2`
ON `Table_1`.`Some_ID` = `Table_2`.`Some_ID`
AND `Table_1`.`Timestamp` = `Table_2`.`Timestamp`
WHERE `Table_1`.`Some_ID` LIKE 'ID %' AND `Table_1`.`Timestamp` LIKE '2018/03/20 %'
ORDER BY `Table_1`.`Some_ID`
LIMIT 0, 5;


因此,我的Access查询有问题吗?
为了完成我的问题,这就是我最终的Access查询的外观(我对上述主题中提出的内容做了一些修改):

查询#4

SELECT *
FROM `Table_1` INNER JOIN `Table_2`
ON `Table_1`.`Some_ID` = `Table_2`.`Some_ID`
AND `Table_1`.`Timestamp` = `Table_2`.`Timestamp`
WHERE EXISTS (
    SELECT TOP 5 * FROM (
        SELECT TOP 10 *
        FROM `Table_1` INNER JOIN `Table_2`
        ON `Table_1`.`Some_ID` = `Table_2`.`Some_ID`
        AND `Table_1`.`Timestamp` = `Table_2`.`Timestamp`
        WHERE `Table_1`.`Some_ID` LIKE 'ID %' AND `Table_1`.`Timestamp` LIKE '2018/03/20 %')
    ORDER BY `Table_1`.`Some_ID` DESC)
ORDER BY `Table_1`.`Some_ID` ASC;

最佳答案

最后,我设法解决了我的问题。我会发布查询,以防其他人遇到同样的问题。

SELECT TOP 5 *
FROM `Table_1` INNER JOIN `Table_2`
ON `Table_1`.`Some_ID` = `Table_2`.`Some_ID`
AND `Table_1`.`Timestamp` = `Table_2`.`Timestamp`
WHERE `Table_1`.`Timestamp`
IN (
    SELECT TOP 5 `Table_1`.`Timestamp`
    FROM (
        SELECT TOP 10 *
        FROM `Table_1` INNER JOIN `Table_2`
        ON `Table_1`.`Some_ID` = `Table_2`.`Some_ID`
        AND `Table_1`.`Timestamp` = `Table_2`.`Timestamp`
        WHERE `Table_1`.`Some_ID` LIKE 'ID %'
        AND `Table_2`.`Timestamp` LIKE '2018/03/20 %'
        ORDER BY `Table_1`.`Timestamp` ASC)
    ORDER BY `Table_1`.`Timestamp` DESC)
ORDER BY `Table_1`.`Timestamp` ASC;


只需使用“ ASC”和“ DESC”来获得您愿意返回的结果。

10-06 07:56
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