Question

我在mysql上运行以下查询

SELECT DATE(field) AS day, COUNT( * ) AS totalSessions
FROM table
GROUP BY DATE(field) 
ORDER BY field DESC 
LIMIT 7

返回

day        |   totalSessions
2013-12-17 |   5
2013-12-15 |   1

我需要更改我的查询以便获得结果

day        |  totalSessions
2013-12-17 |  5
2013-12-16 |  0
2013-12-15 |  1
2013-12-14 |  0
2013-12-13 |  0
2013-12-12 |  0
2013-12-11 |  0

Answer 1

您可能需要存储（某处）要返回的日期。我认为存储过程可以帮助您：

delimiter $$
create procedure getStuff(d0 date, d1 date)
begin
    declare d date;
    drop table if exists temp_dates;
    create temporary table temp_dates (
         d date not null primary key
    );
    set d = d0;
    while d <= d1 do
        insert into temp_dates values (d);
        set d = date_add(d, interval +1 day);
    end while;
    select 
        a.d as day,
        count(b.field) as totalSessions
    from
        temp_dates as a
        left join yourTable as b on a.d = b.dateField -- Assuming "dateField" holds the date
    group by
        a.d;
end $$
delimiter ;

希望这有帮助

Answer 2

不是最好看的解决方案，但值得一试：

SELECT 
    FAKE.dt, 
    COUNT(YT.id) AS totalSessions 
FROM (
    SELECT DATE(NOW()) as dt
    UNION SELECT DATE(DATE_SUB(NOW(), INTERVAL 1 DAY)) as dt
    UNION SELECT DATE(DATE_SUB(NOW(), INTERVAL 2 DAY)) as dt
    UNION SELECT DATE(DATE_SUB(NOW(), INTERVAL 3 DAY)) as dt
    UNION SELECT DATE(DATE_SUB(NOW(), INTERVAL 4 DAY)) as dt
    UNION SELECT DATE(DATE_SUB(NOW(), INTERVAL 5 DAY)) as dt
    UNION SELECT DATE(DATE_SUB(NOW(), INTERVAL 6 DAY)) as dt
) FAKE
LEFT JOIN yourtable YT ON YT.datefield = FAKE.dt
GROUP BY FAKE.dt
ORDER BY FAKE.dt DESC

所以你从今天开始向后选择7个日期，结合结果，左边加入你需要的数据，分组和按日期排序。

从mysql“count（）”返回0的计数

2 个答案: