我正在开发一个PHP接口来显示来自两个不同数据库的一些结果:一个MySQL(.sql)和一个Access(.mdb)。当我查询结果时,我让用户选择他想要列出的数量,这样我就可以通过一些PHP乐趣来限制和分页。
这对于MySQL DB来说是完美无缺的,其中 LIMIT 子句以一种简洁的方式完成所有事情。 Access DB是一个不同的说法:Access没有LIMIT子句,所以我要使用 TOP 子句。太糟糕了,这个让后面的分页变得痛苦
我在this question的接受答案中找到了一个很好的例子,但我遇到了问题。首先,让我向您展示几个片段查询:
QUERY#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 %';
QUERY#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`;
查询#1 按要求向我显示前5个结果 太糟糕了,当我添加 ORDER BY 子句时,查询#2 会让我回复满足条件的所有结果。
对于像这样的MySQL查询,同样的事情不会发生:
QUERY#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;
那么,我是否在使用Access查询时出错? 要完成我的问题,这是我的最终Access查询应该是这样的(我稍微修改了上述主题中提出的那个):
QUERY#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;
答案 0 :(得分:0)
最后我设法解决了我的问题。我会发布我的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”即可获得您愿意回复的结果。