Question

SELECT today.status, GROUP_CONCAT(tomorrow.work_order order by line), today.code, today.events  
FROM today LEFT JOIN tomorrow 
   ON today.code = tomorrow.code   
   WHERE today.status like '1%' or  
      (today.status like '3%' and tomorrow.work_ordertext is null) 
      GROUP BY today.code

我遇到'tomorrow.work_ordertext is null'语句的问题。 tomorrow.code和tomorrow.work_ordertext甚至可能不存在于表中，所以我猜它不应该是一个空语句。我正在寻找一种方法来从今天的表中提取行，如果在今天的表中状态为3时明天表上没有记录。对不起，如果这听起来很混乱。

Answer 1

SELECT today.status, GROUP_CONCAT(tomorrow.work_order order by line), today.code, today.events  
  FROM today LEFT JOIN tomorrow   
ON today.code = tomorrow.code   
WHERE today.status = 1 or    
  (today.status = 3 and isnull( tomorrow.work_ordertext ))  
  GROUP BY today.code

我取出了类似的状态，因为它将匹配1,10,1b，1somethingweird。

查询不存在的记录

1 个答案: