mysql - 如何获取不在下一个表格MySQL中的数据

我有返回所有数据的mysql查询

SELECT state,`County`,`CountyFIPS`,count(`email_address`) as email
FROM `campaign_emails`
Where state='AK'
  AND CountyFIPS NOT IN
   (select group_concat(`county_fipscode` separator ',')
    from order_cart where flyer_id='1' AND user_id='400'
   )
GROUP BY `CountyFIPS`

但是当我手动传递相同的查询时，它返回我的确切值

SELECT state,`County`,`CountyFIPS`,count(`email_address`) as email
FROM `campaign_emails`
Where state='AK'
  AND CountyFIPS NOT IN (02261,02220,02180,02170,02240,02020,02090,02110)
GROUP BY `CountyFIPS`

请帮助任何人，原因是什么？

最佳答案

IN接受SELECT查询的结果，但是一个以逗号分隔的值作为硬编码字符串的字符串只会被视为1个值，因此第一个查询中的所有内容都将匹配。
Mysql将第一个查询中的条件视为：

... AND CountyFIPS NOT IN ('1,2,3,4,5')    // this is not the array of values you want to use

因此，您可以将代码简化为：

SELECT state,County,CountyFIPS,count(email_address) as email
FROM campaign_emails Where state='AK'
    AND CountyFIPS NOT IN (select county_fipscode from order_cart where flyer_id='1' AND user_id='400') GROUP BY CountyFIPS
                                  ^^^^^^^^^^^^^^^ here