mysql - mysql ，从选择结果更新

Question

我正在尝试执行类似的操作：

              UPDATE page_results
          SET cache_valid=0
          WHERE link_id IN (SELECT  DISTINCT  l.link_id
          FROM link_results AS l
          INNER JOIN page_results AS p ON p.link_id=p.link_id 
          WHERE has_no_robots=0 AND cache_valid=1 AND cache_to_expire=1 AND status_code!='404' AND  href!='' AND anchor_match!='' AND nofollow=0)

基本上，我想更新从派生表中获取的所有结果。

我的另一个解决方案是：

              UPDATE (SELECT  DISTINCT  l.link_id
          FROM link_results AS l
          INNER JOIN page_results AS p ON p.link_id=p.link_id 
          WHERE has_no_robots=0 AND cache_valid=1 AND cache_to_expire=1 AND status_code!='404' AND  href!='' AND anchor_match!='' AND nofollow=0) 
          SET cache_valid=0

但这也不起作用..有没有办法实现我的目标？

Answer 1

这是执行此操作的正确语法：

UPDATE page_results t1
INNER JOIN link_results AS l ON t1.link_id = l.link_id 
SET t1.cache_valid = 0
WHERE t1.has_no_robots   = 0 
  AND t1.cache_valid     = 1 
  AND t1.cache_to_expire = 1 
  AND t1.status_code    != '404' 
  AND t1.href!           = '' 
  AND t1.anchor_match   != '' 
  AND t1.nofollow        = 0;

Answer 2

这是因为p.link_id=p.link_id join 子句条件错误，试试这个查询：

  UPDATE page_results p
         INNER JOIN link_results l
             ON p.link_id = l.link_id
  SET   p.cache_valid = 0
  WHERE has_no_robots = 0 AND
        cache_valid = 1 AND 
        cache_to_expire = 1 AND
        status_code != '404' AND
        href != '' AND
        anchor_match != '' AND
        nofollow = 0;