Question

此查询返回is_message ='on'和mass_message ='on'

的行

SELECT * 
FROM `messages` 
WHERE 
  (`sender_id` = '111' AND `recipient_id` = '222')
  OR (`sender_id` = '222' AND `recipient_id` = '111')
  AND (`is_message` != 'on' OR `is_message` IS NULL)
  AND (`mass_message` != 'on' OR `mass_message` IS NULL)
  AND `invite_for_lunch` = 'on'
LIMIT 0 , 30

如何确保它只返回在{

上invite_for_lunch ='的行

这最初是一个计数，但我想查看返回的行。

我检查了列，而is_message，mass_message，invite_for_lunch）中的两列没有on在同一行。

预期结果：应返回5行

Answer 1

尝试修复括号

SELECT * 
FROM `messages` 
WHERE 
 (  
        (`sender_id` = '111' AND `recipient_id` = '222')
     OR (`sender_id` = '222' AND `recipient_id` = '111') 
  )
  AND (`is_message` != 'on' OR `is_message` IS NULL)
  AND (`mass_message` != 'on' OR `mass_message` IS NULL)
  AND `invite_for_lunch` = 'on'
LIMIT 0 , 30

如果没有额外的括号，第一个OR最有可能被错误处理

Answer 2

将您的WHERE更改为

WHERE ((`sender_id` = '111'
           AND `recipient_id` = '222')
       OR (`sender_id` = '222'
           AND `recipient_id` = '111')
      )
    AND ....

Answer 3

也许这就是你想要的？

SELECT    <Insert columns names here as select * is a SQL antipattern>
FROM `messages` 
WHERE 
 (  
        (`sender_id` = '111' AND `recipient_id` = '222')
     OR (`sender_id` = '222' AND `recipient_id` = '111') 
  )
  AND 
  (
        (`is_message` != 'on' OR `is_message` IS NULL)
     OR (`mass_message` != 'on' OR `mass_message` IS NULL)
   )
  AND `invite_for_lunch` = 'on'
LIMIT 0 , 30

查询不返回正确的行

3 个答案: