我正在编写一个查询以获取表中的所有产品products
,以及每个产品的销售价格(如果表中存在该项目的记录)specials
。
我正在寻找的是这样的:
SELECT * FROM products P
IF (S.specials_date_available <= NOW() AND S.expires_date > NOW())
{ // The sale has started, but has not yet expired
LEFT JOIN specials S
ON P.products_id = S.products_id
}
我意识到 MySQL 不是一种编程语言,但是有没有办法创建一个查询来产生与上述逻辑等价的结果?
结果集应如下所示:
ID Name Price Sale Price
1 Widget A 10.00 (empty, because this item has no sale record)
2 Widget B 20.00 15.45 (this item is currently on sale)
3 Widget C 22.00 (empty - this item was on sale but the sale expired)