Question

如何在一个查询中合并这两个sql查询？

$query2 ="select raiting.rated_user,avg(raiting.rate) as `avg_rating` from raiting,users  where
raiting.rated_user=user_id  group by raiting.rated_user order by avg(raiting.rate) desc";

$query      = “SELECT `user_id`,`name`,`email`,`degree`,`avatar`,`mobile`,`sex`,`nationality`,`nationalitycode`,`birthday_year`,`pr_hour`,`spicality`,`city`,`online`,`intro`, (SQRT(POW((lat - $lat), 2) + POW((lang - $lang), 2)) * $multiplier) AS distance FROM users  WHERE POW((lat - $lat), 2) + POW((lang - $lang), 2) < POW(($distance / $multiplier), 2) ORDER BY distance";

Answer 1

在第二个中使用第一个作为子查询：

$query = "
 SELECT
      `user_id`,`name`,`email`,`degree`,`avatar`,`mobile`
      ,`sex`,`nationality`,`nationalitycode`,`birthday_year`,`pr_hour`
      ,`spicality`,`city`,`online`
      ,`intro`
      , (SQRT(POW((lat - $lat), 2) + POW((lang - $lang), 2)) * $multiplier) AS distance 
      , r.`avg_rating`
 FROM users 
 INNER JOIN (
      select
            raiting.rated_user
           ,avg(raiting.rate) as `avg_rating` 
      from raiting
      group by raiting.rated_user 
      ) AS r  on users.user_id  = raiting.rated_user
 WHERE POW((lat - $lat), 2) + POW((lang - $lang), 2) < POW(($distance / $multiplier), 2) 
 ORDER BY distance
";

SQL查询可以分布在多行上，使维护更容易

采取预防措施以避免SQL注入

Answer 2

你也可以试试这个：

$query = "SELECT `user_id`,`name`,`email`,`degree`,`avatar`, `mobile`,`sex`,`nationality`, `nationalitycode`,`birthday_year`,`pr_hour`,
`spicality`,`city`,`online`,`intro`,t1.rated_user,t1.avg_rating
(SQRT(POW((lat - $lat), 2) + POW((lang - $lang), 2)) * $multiplier) AS distance 
FROM users inner join (select raiting.rated_user,avg(raiting.rate) as `avg_rating` from raiting 
group by raiting.rated_user 
order by avg(raiting.rate) desc) t1 on users.user_id = t1.rated_user
WHERE POW((lat - $lat), 2) + POW((lang - $lang), 2) < POW(($distance / $multiplier), 2) 
ORDER BY distance";

合并2 sql查询位置和平均评级

2 个答案: