dtl4521 2010-12-28 10:31
浏览 40
已采纳

按间隔显示零的组

I'm trying to group a query by intervals in this way:

SELECT COUNT( * ) AS count, i.date
    FROM intervals i
    LEFT JOIN dtracker dt ON 
    i.date <= dt.date AND i.date + INTERVAL (NUMSEC) SECOND >= dt.date
    WHERE (SOME CONDITIONS)
    GROUP BY i.date

where I fill the table 'intervals' each time (cause intervals can change), and NUMSEC is changing as well depending of the intervals table.

Everything is working fine without 'WHERE', if there´s not results in some intervals, it shows 0 intervals. But if I put some conditions in 'WHERE' and there's no results, it doesn't show this interval anymore.

Seems like 'WHERE' clauses affects the whole query (it makes sense) but I need it to affect only to dtracker table. How I can do this?

Thanks a lot in advance.

  • 写回答

2条回答 默认 最新

  • drfb52000 2010-12-28 10:37
    关注

    Replace WHERE with another AND so that the conditions become part of the LEFT JOIN ... ON clause.

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
    评论
查看更多回答(1条)

报告相同问题?

悬赏问题

  • ¥16 Qphython 用xlrd读取excel报错
  • ¥15 单片机学习顺序问题!!
  • ¥15 ikuai客户端多拨vpn,重启总是有个别重拨不上
  • ¥20 关于#anlogic#sdram#的问题,如何解决?(关键词-performance)
  • ¥15 相敏解调 matlab
  • ¥15 求lingo代码和思路
  • ¥15 公交车和无人机协同运输
  • ¥15 stm32代码移植没反应
  • ¥15 matlab基于pde算法图像修复,为什么只能对示例图像有效
  • ¥100 连续两帧图像高速减法