Question

我有2张桌子 - 情绪＆amp;评论 - 我正在尝试根据mysql中的一组派生时间范围加入平均值和计数。

这就是我个人的作品：

  SELECT ROUND(AVG(sentiment.sent_value)) AS sentiment,
         ROUND( FLOOR( (sentiment.sent_video_time) /5000 ) *5000 ) AS start_time, ' - ', 
         ROUND( (FLOOR( (sentiment.sent_video_time) /5000 ) +1 ) *5000) AS end_time
    FROM sentiment
GROUP BY end_time

...和...

  SELECT COUNT(comment.commID) AS comments,
         ROUND( FLOOR( (comment.c_video_time) /5000 ) *5000 ) AS ctime, ' - ', 
         ROUND( (FLOOR( (comment.c_video_time) /5000 ) +1 ) *5000) AS cend_time
    FROM comment
GROUP BY ctime

时间增量始终匹配。每个时间增量总会有情绪值，但并不总是评论。

我正在尝试将组合表输出：

sentiment,  comments,    start_time - end_time
-----------------------------------------------
65,         8,           0 - 5000
42,         0,           5000 - 10000
35,         17,          10000 - 15000

谢谢！

UPDATE：

由于以下答案，我已经进一步了解。这会返回正确的数据，但如果没有相应情绪时间段的注释，则会排除这些行。我希望它在该部分的评论中显示“0”。

我知道这是因为我定义“GROUP BY”的方式，但是如果在给定的时间内对0+评论有0评论，我就无法确定处理的正确条件。

SELECT x.sentiment AS senti,
       y.comments AS comments,
       x.start_time AS time
 FROM (SELECT campaign_campID,
              ROUND(AVG(sentiment.sent_value)) AS sentiment,
              ROUND( FLOOR( (sentiment.sent_video_time) /5000 ) *5000 ) AS start_time, ' - ', 
              ROUND( (FLOOR( (sentiment.sent_video_time) /5000 ) +1 ) *5000) AS end_time
         FROM sentiment
     GROUP BY start_time, campaign_campID) x
 JOIN (SELECT campaign_campID,
              CASE 
                WHEN COUNT(comment.commID) =  NULL THEN 0 
                ELSE COUNT(comment.commID) 
              END AS comments,
              ROUND( FLOOR( (comment.c_video_time) /5000 ) *5000 ) AS cstart_time, ' - ', 
              ROUND( (FLOOR( (comment.c_video_time) /5000 ) +1 ) *5000) AS cend_time
         FROM comment
     GROUP BY cstart_time, campaign_campID) y ON y.campaign_campid = x.campaign_campid
WHERE y.cstart_time = x.start_time
GROUP BY x.start_time

以下是表格：

CREATE TABLE comment ( 
    commID INT NOT NULL AUTO_INCREMENT , 
    campaign_campID INT NULL DEFAULT NULL , 
    c_video_time BIGINT(20) NULL 
) 

CREATE TABLE sentiment ( 
    campaign_campID INT NULL , 
    sent_value TINYINT NULL , 
    sent_video_time BIGINT(20) NULL 
) ENGINE = InnoDB DEFAULT CHARACTER SET = utf8 COLLATE = utf8_unicode_ci

Answer 1

左表连接表评论与表情绪。在内部查询中使用Coalesce而不是case 如果表情绪有0行，则y.comments = NULL，因此coalesce（NULL，0）将返回0

SELECT x.sentiment AS senti,
       COALESCE(y.comments,0) AS comments,
       x.start_time AS time
 FROM (SELECT campaign_campID,
              ROUND(AVG(sentiment.sent_value)) AS sentiment,
              ROUND( FLOOR( (sentiment.sent_video_time) /5000 ) *5000 ) AS start_time, ' - ', 
              ROUND( (FLOOR( (sentiment.sent_video_time) /5000 ) +1 ) *5000) AS end_time
         FROM sentiment
     GROUP BY start_time, campaign_campID) x
 LEFT JOIN (SELECT campaign_campID, COUNT(comment.commID)  comments
              ROUND( FLOOR( (comment.c_video_time) /5000 ) *5000 ) AS cstart_time, ' - ', 
              ROUND( (FLOOR( (comment.c_video_time) /5000 ) +1 ) *5000) AS cend_time
         FROM comment
     GROUP BY cstart_time, campaign_campID) y ON x.campaign_campid = y.campaign_campid AND  x.start_time = y.cstart_time

根据一组计算的时间范围mysql拉平均值和计数

UPDATE：

1 个答案: