MySQL查询concatination错误

Question

谁能告诉我什么是错误的与查询

$sql = "SELECT * FROM user_monsoon_offer WHERE DATE_ADD(start_date,INTERVAL 4 DAY) = ' ".$date." ' AND user_monsoon_offer.user_id NOT IN (SELECT user_id FROM transactions)"; 

Answer 1

我相信你在串联有多余的空格引起的问题。试试这个：

$sql = "SELECT * FROM user_monsoon_offer 
     WHERE DATE_ADD(start_date,INTERVAL 4 DAY) = '$date' 
     AND user_monsoon_offer.user_id NOT IN (SELECT user_id FROM transactions)"; 

你原来WHERE条款看起来像下面这样：

WHERE DATE_ADD(start_date,INTERVAL 4 DAY) = ' 2016-06-21 ' 

，因为多余的空格这将无法正常工作。

Answer 2

我相信你在过滤条件下寻找动态数据连接。使用下面的条件。

SELECT * FROM user_monsoon_offer 
WHERE SUBDATE(start_date,4) = ' ".$date." ' 
    AND user_monsoon_offer.user_id NOT IN (SELECT user_id FROM transactions);