Question

SELECT * 
FROM 
( 
  SELECT com_jobcard.job_card_num, 
    sum( worked_qty ),employee.emp_name
  FROM timer_completed
  INNER JOIN process ON process.id = timer_completed.process_id
  INNER JOIN com_jobcard ON com_jobcard.id = timer_completed.job_card_id
  INNER JOIN employee ON employee.id = timer_completed.employee_id
                                   AND process.id = '611'
                                   AND timer_completed.group_id = '60'
    AND timer_completed.report_date = DATE_ADD(CURDATE(), INTERVAL -1 DAY)
  ORDER BY com_jobcard.id DESC 
) AS tmp_table 
GROUP BY com_jobcard.job_card_num

在此代码中，我使用Group by选项，但如果我使用上面的查询返回，我需要com_jobcard.id的降序结果：

#1054 - 未知栏＆＃39; com_jobcard.job_card_num＆＃39;在＆＃39;组声明＆＃39;

请帮帮我。

Answer 1

使用

GROUP BY tmp_table.job_card_num

Answer 2

两件事： 1）子查询中的所有列都需要命名。这将清除错误＃1054

Foo.SOME_CONSTANT_STRING

2）如果使用“Top Select”子句，则Order by仅在Subqueries中可用。您需要使用Order by Where by group by，反之亦然

Answer 3

您在这里不必要地嵌套查询。您可以通过将ORDER BY放在GROUP BY之后来订购汇总查询结果集。此外，就像戈登在评论中指出的那样，你正在滥用非标准的MySql扩展名GROUP BY。除非你了解它，否则这会让你发疯。 https://dev.mysql.com/doc/refman/5.6/en/group-by-handling.html

尝试重构您的查询，如下所示：

SELECT com_jobcard.job_card_num, 
        sum( worked_qty),
        employee.emp_name,
        com_jobcard.id
   FROM timer_completed
   JOIN process ON process.id = timer_completed.process_id
   JOIN com_jobcard ON com_jobcard.id = timer_completed.job_card_id
   JOIN employee ON employee.id = timer_completed.employee_id
                AND process.id = '611'
                AND timer_completed.group_id = '60'
                AND timer_completed.report_date = DATE_ADD(CURDATE(), INTERVAL -1 DAY)
  GROUP BY com_jobcard.job_card_num,  employee.emp_name, com_jobcard.id
  ORDER BY com_jobcard.id DESC

除了比你提出的查询更简单之外，它正确处理GROUP BY并产生你指定的顺序。

在同一查询上使用Groupby和Orderby

3 个答案: