如何将另一列的整数值添加到日期列？

Question

我试图在日期中添加一个整数，但是我收到以下错误：

＃1064 - 您的SQL语法出错;检查与您的MySQL服务器版本相对应的手册，以便使用接近＆＃39;（wp.OrderDate，INTERVAL WPProduct.Duration DAY）AS ExpiryDate FROM wp＆＃39;第6行

SELECT 
wp.customers_id, 
wp.OrderDate, 
wp.products_id,
WPProduct.Duration,
DATE_ADD (wp.OrderDate, INTERVAL WPProduct.Duration DAY) AS ExpiryDate
FROM wp 
INNER JOIN WPProduct ON WPProduct.products_id = wp.products_id
WHERE wp.customers_id = 2

Answer 1

在DATE_ADD后删除空格：

SELECT 
wp.customers_id, 
wp.OrderDate, 
wp.products_id,
WPProduct.Duration,
DATE_ADD(wp.OrderDate, INTERVAL WPProduct.Duration DAY) AS ExpiryDate
FROM wp 
INNER JOIN WPProduct ON WPProduct.products_id = wp.products_id
WHERE wp.customers_id = 2