Question

我看到了另一个问题的答案，这就是我如何开始，但我无法让我的代码工作。我认为它与（Price＆gt;'0.00'）有关，因为mysql一直给我这个错误，

“＃1064 - 您的SQL语法有错误;请查看与您的MySQL服务器版本对应的手册，以便在'ORDER BY Price = 0，Price asc，Style asc，Manufacturer asc END WHEN附近使用正确的语法（（价格＆lt; ='在第8行“。

<?php 
$order = mysqli_query($con, "SELECT DivisionOf, Manufacturer, Style, Include,
Fiber, Width, Backing
FROM CarpetInfo

WHERE (DivisionOf='Mohawk') AND (Manufacturer IN ('Aladdin'))
AND CASE
WHEN (Price > '0.00') AND (Price <= '49.95') AND (ShowPrice='Yes')
THEN ORDER BY Price = 0, Price asc, Style asc, Manufacturer asc
END

WHEN ((Price <= '0.00') OR (Price > '49.95') OR (ShowPrice!='Yes'))
THEN ORDER BY Price = 0, Style asc, Manufacturer asc
END
");
$result = mysqli_fetch_row($order);

mysqli_data_seek($order, 0);
while($info = mysqli_fetch_array( $order ))
include($_SERVER['DOCUMENT_ROOT'].$info['Include']);?>

Answer 1

跟进我的评论。

您无法将整个ORDER BY条款放入CASE声明中
每END个CASE是允许的（在案例陈述的最后）

相反，以下内容应该有效：

SELECT DivisionOf, Manufacturer, Style, Include,Fiber, Width, Backing
FROM CarpetInfo
WHERE (DivisionOf='Mohawk') AND (Manufacturer IN ('Aladdin'))
ORDER BY
    /*sort field 1*/
    CASE
        WHEN (Price > '0.00') AND (Price <= '49.95') AND (ShowPrice='Yes')
            THEN Price
        WHEN ((Price <= '0.00') OR (Price > '49.95') OR (ShowPrice!='Yes'))
            THEN Style
    END asc,
    /*sort field 2*/
    CASE
        WHEN (Price > '0.00') AND (Price <= '49.95') AND (ShowPrice='Yes')
            THEN Style
        WHEN ((Price <= '0.00') OR (Price > '49.95') OR (ShowPrice!='Yes'))
            THEN Manufacturer
    END asc,
    /*sort field 3*/
    CASE
        WHEN (Price > '0.00') AND (Price <= '49.95') AND (ShowPrice='Yes')
            THEN Manufacturer       
    END asc;

这有点难看，因为你只能从case语句中返回一个字段，然后在你END之后的那个ORDER BY字段的情况下指定方向。

另外，虽然我不熟悉您的数据。我认为可以使用CASE简化这些ELSE语句：

SELECT DivisionOf, Manufacturer, Style, Include,Fiber, Width, Backing
FROM CarpetInfo
WHERE (DivisionOf='Mohawk') AND (Manufacturer IN ('Aladdin'))
ORDER BY
    CASE WHEN (Price > '0.00') AND (Price <= '49.95') AND (ShowPrice='Yes') THEN Price ELSE Style END asc,
    CASE WHEN (Price > '0.00') AND (Price <= '49.95') AND (ShowPrice='Yes') THEN Style ELSE Manufacturer asc,
    CASE WHEN (Price > '0.00') AND (Price <= '49.95') AND (ShowPrice='Yes') THEN Manufacturer END asc;

更新：因为我们正在混合字段类型，所以在某些情况下，您最终会使用词典排序而不是数字。一些放在案例陈述中的人应该有所帮助：

SELECT DivisionOf, Manufacturer, Style, Include,Fiber, Width, Backing
FROM CarpetInfo
WHERE (DivisionOf='Mohawk') AND (Manufacturer IN ('Aladdin'))
ORDER BY
    CASE WHEN (Price > '0.00') AND (Price <= '49.95') AND (ShowPrice='Yes') THEN Price ELSE 0 END asc,
    CASE WHEN (Price > '0.00') AND (Price <= '49.95') AND (ShowPrice='Yes') THEN NULL ELSE Style END asc,
    CASE WHEN (Price > '0.00') AND (Price <= '49.95') AND (ShowPrice='Yes') THEN Style ELSE Manufacturer asc,
    CASE WHEN (Price > '0.00') AND (Price <= '49.95') AND (ShowPrice='Yes') THEN Manufacturer END asc;

所以现在第一个要点击的是price中的值或0，然后style被移动到第二个排序顺序。你不得不四处闲逛，让它随你工作。

无法通过Case获得在Mysql中工作

1 个答案: