mysql - 如何用两个表写sql命令？

table **salesrule_coupon**: fileds as the following:

           coupon_id   code

             1        Registered_send_5
             2         test

表：salesrule_coupon_usage文件如下：

    coupon_id  customer_id   times_used

    1               1          1
    1
   ...              14 ...       1..

现在，我想选择times_usedwhere thecode =Registered_send_5where customer_id=$id。如何编写sql命令？谢谢你。
以下是我的，但不起作用。

$sql = "SELECT times_used FORM salesrule_coupon_usage as a
       left join  salesrule_coupon as b on a.coupon_id  = b.coupon_id
       where b.code = 'Registered_send_5' and   customer_id=".'$id.";

当我把

  SELECT times_used FORM salesrule_coupon_usage as a
           left join  salesrule_coupon as b on a.coupon_id  = b.coupon_id
           where b.code = 'Registered_send_5' and   customer_id=1

在phpmyadmin。它显示
您的SQL语法有错误；请查看对应于MySQL服务器版本的手册，在第1行的“salesrule_coupon_usage as a left join salesrule_coupon as b on a.co”附近使用正确的语法

最佳答案

有一个撇号（单引号）不应该在那里，你错拼了“from”：

$sql = "SELECT times_used FORM salesrule_coupon_usage as a
                           ^
   left join  salesrule_coupon as b on a.coupon_id  = b.coupon_id
   where b.code = 'Registered_send_5' and   customer_id= ".'$id;
                                                           ^