php ORDER BY日期似乎不起作用

Question

我想只显示折扣最新的图书。 Dealstart和Dealend代表了这个窗口。但我搞砸了。

$sqlCommand = "SELECT id,bookcover FROM booklist WHERE category1='$bookid' OR category2='$bookid' OR category3='$bookid' AND dealstart >= CURDATE() AND dealend is >= CURDATE()"; 

Answer 1

它看起来像有一个在你的SQL语句中的语法错误，删除“是”：

lCommand = "SELECT id,bookcover FROM booklist WHERE category1='$bookid' OR category2='$bookid' OR category3='$bookid' AND dealstart >= CURDATE() AND dealend >= CURDATE()"; 

如果查询仍然不工作，回声“lCommand”，看看它的生产，然后尝试对数据库运行该查询。

Answer 2

是否这样？

$sqlCommand = "SELECT 
        id, 
        bookcover 
       FROM 
        booklist 
       WHERE 
        category1='$bookid' OR 
        category2='$bookid' OR 
        category3='$bookid' AND 
        dealstart >= CURDATE() AND 
        dealend >= CURDATE() 
       ORDER BY 
        dealend DESC";