比较 mysql select 和 table 并且只使用没有匹配的结果

Question

我创建了以下查询，它选择了我需要的数据

SELECT par.wo, l.addr, eml.maildate, lp.workdate
FROM parsed AS par, emails AS eml, list AS l, locateparsed AS lp
WHERE par.status != 0 AND eml.id = par.origid AND par.wo = l.wo AND par.wo = lp.wo

是否可以让每个返回的行在 "completed" table 中检查匹配 'wo' 并且如果使用一个查询匹配则不输出它？

Answer 1

这正是为什么 from 中的逗号分隔表让我如此恼火的原因，您只是看不到连接类型使用的明显性。试试这个：

SELECT
  par.wo,
  l.addr,
  eml.maildate,
  lp.workdate
FROM
  parsed AS par
  INNER JOIN emails AS eml      ON eml.id = par.origid
  INNER JOIN list AS l          ON par.wo = l.wo
  INNER JOIN locateparsed AS lp ON par.wo = lp.wo
  LEFT  JOIN completed          ON par.wo = completed.wo
WHERE
  par.status != 0 
  AND completed.wo IS NULL

比较 mysql select 和 table 并且只使用没有匹配的结果

Compare mysql select to table and only use results with no match

mysql

sql

inner-join