mysql查詢按日期獲取行數據的最大計數？

Question

我有一個表名稱為a_ad_display，並具有以下列

displayId | campaignId | displaytime(date)

1          |    2      | 2012-12-19 12:41:08
2          |    2      | 2012-12-19 01:41:08
3          |    1      | 2012-12-20 10:41:08
4          |    1      | 2012-12-20 02:41:08
5          |    1      | 2012-12-21 12:41:08
6          |    2      | 2012-12-21 01:41:08
7          |    1      | 2012-12-21 12:41:08
8          |    1      | 2012-12-21 02:41:08

現在應該要有多個具有相同CampaignId的條目。現在我想要的是首先獲取a_ad_display中具有最高計數的campaignId，對於該CampaignId，我想獲取日期內的總數

例如..從上表中，我有1個CampaignId，其行數最高

所以對於1個編號campaignId我想顯示這樣的記錄。

        **Date**     | **countPerDay**
 2012-12-19          |      0
 2012-12-20          |      2
 2012-12-21          |      3

我如何在mysql數據庫中實現這一目標...希望任何人都可以指導我...

Answer 1

您可以使用此查詢

select 
    count(campaignId) as TCount,
    DATE(displayTime) as `Date`
from a_ad_display
where campaignId = 1
group by DATE(displayTime)

雖然不會顯示0。

編輯：

確定這將被修改並獲取您的結果。

select
  date(a.displayTime) as `DisplayTime`,
  ifnull(l.TCount,0) as TCount
from a_ad_display as a
  left join (select
           count(campaignId) as TCount,
           displayTime
         from a_ad_display
         where campaignId = 1
         group by DATE(displayTime)) as l
    on date(a.displayTime) = date(l.displayTime)
group by DATE(a.displayTime)

演示版

更多編輯：

select
  date(a.displayTime) as `DisplayTime`,
  ifnull(l.TCount,0) as TCount
from a_ad_display as a
  left join (select
           count(campaignId) as TCount,
           displayTime
         from a_ad_display
         where campaignId = 1
         group by DATE(displayTime)) as l
    on date(a.displayTime) = date(l.displayTime)
group by DATE(a.displayTime)
order by a.displaytime desc limit 5

這樣您可以選擇最新的5條記錄。 如果您想選擇最新的廣告系列，則可以使用子查詢代替1，以查看此查詢

select
  date(a.displayTime) as `DisplayTime`,
  ifnull(l.TCount,0) as TCount
from a_ad_display as a
  left join (select
       count(campaignId) as TCount,
       displayTime
     from a_ad_display
     where campaignId = (select  campaignId from a_ad_display group by campaignId order by count(campaignId) desc limit 1)
     group by DATE(displayTime)) as l
    on date(a.displayTime) = date(l.displayTime)
group by DATE(a.displayTime)

編輯：

我已經編輯了查詢，它將獲取更高的出現率CampaignId並相應地獲取結果

演示版

Answer 2

這也將顯示0

 select 
       sum(case when campaignId = @inputCompainid then 1 else 0 end) as TCount, 
        DATE(displayTime) as `Date`
    from a_ad_display
    group by DATE(displayTime)

Answer 3

以下查詢為您提供每個campaignId的記錄列表

select campaignId,date(displaytime) as Date,count(*) as countPerDay from a_ad_display group by campaignId,date(displaytime);

如果您需要特定的campaignId，請使用以下代碼：

select campaignId,date(displaytime) as Date,count(*) as countPerDay from a_ad_display group by campaignId,date(displaytime) having campaignId=1;

Answer 4

很想問這個，但是這個查詢哪個更好？？

1. 山大先生的回答

EXPLAIN SELECT DATE(a.displayTime) AS `DisplayTime`,IFNULL(l.TCount,0) AS TCount
FROM a_ad_display AS a
LEFT JOIN (SELECT
       COUNT(campaignId) AS TCount,
       displayTime
     FROM a_ad_display
     WHERE campaignId = 1
     GROUP BY DATE(displayTime)) AS l
ON DATE(a.displayTime) = DATE(l.displayTime)
GROUP BY DATE(a.displayTime);


id  select_type  table         type  possible_keys  key  key_len  ref  rows  Extra                                            
1   PRIMARY      <derived2>    ALL                                     2                                                   
1   PRIMARY      a             ALL                                     8     Using temporary; Using filesort               
2   DERIVED      a_ad_display  ALL                                     8     Using where; Using temporary; Using filesort  

2.或使用這個

EXPLAIN SELECT DATE(a_ad_display.`displaytime`) AS `DATE`, 
               COUNT(a.`campaignId`) AS `COUNT Per Day` 
        FROM a_ad_display 
        LEFT JOIN (SELECT `a_ad_display`.`displayId`,
                          `a_ad_display`.`campaignId` 
                   FROM `a_ad_display` 
                   WHERE `a_ad_display`.`campaignId`=1) a 
        ON (`a_ad_display`.`displayId`=a.`displayId`)
        GROUP BY `a_ad_display`.`displaytime`;

id  select_type  table         type  possible_keys  key  key_len  ref  rows  Extra                              
1   PRIMARY      a_ad_display  ALL                                     8     Using temporary; Using filesort  
1   PRIMARY      <derived2>    ALL                                     5                                       
2   DERIVED      a_ad_display  ALL                                     8     Using where                      

謝謝之前和之后：D

編輯最高的CampaignId發生率

SELECT DATE(a_ad_display.`displaytime`) AS `DATE`, COUNT(a.`campaignId`) AS `COUNT Per Day` FROM a_ad_display 
LEFT JOIN (SELECT `a_ad_display`.`displayId`,`a_ad_display`.`campaignId` FROM `a_ad_display`
   INNER  JOIN (SELECT COUNT(`a_ad_display`.`campaignId`) AS `count`, `a_ad_display`.`campaignId` 
        FROM `a_ad_display` 
        GROUP BY `a_ad_display`.`campaignId` 
        ORDER BY `count` DESC 
        LIMIT 1) b ON (a_ad_display.`campaignId`=b.`campaignId`)
   ) a ON (`a_ad_display`.`displayId`=a.`displayId`)
GROUP BY `DATE`;

GROUP BY a_ad_display 。 displaytime ; / *此聲明中的錯誤...，抱歉* /它應該現在可以正常工作...再試一次。 您可以在這里http://sqlfiddle.com/#!2/bc75b/1簽入，希望它可以在：D中使用