MySQL查询结果全天候

Question

I need to get data for all hours of day, even if the count is 0. Right now it outputs:

clicks--hour
 1----- 7
 2----- 13

My query right now:

SELECT count(*) as clicks, hour(time) as hour FROM clicks WHERE DATE(time) = DATE(NOW()) GROUP BY hour

Thank you for your time

#

Solved, managed to do it on my own, some how.

 SELECT h.Hour , COUNT(id) AS clicks FROM ( SELECT 0 AS Hour UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9 UNION ALL SELECT 10 UNION ALL SELECT 11 UNION ALL SELECT 12 UNION ALL SELECT 13 UNION ALL SELECT 14 UNION ALL SELECT 15 UNION ALL SELECT 16 UNION ALL SELECT 17 UNION ALL SELECT 18 UNION ALL SELECT 19 UNION ALL SELECT 20 UNION ALL SELECT 21 UNION ALL SELECT 22 UNION ALL SELECT 23) AS h LEFT OUTER JOIN clicks ON hour(time) = h.Hour AND DATE(time) = date(now()) GROUP BY h.Hour 

Answer 1

You can use the COALESCE This command helps in the case that a select returns null, to replace null with a value like this:

SELECT 
    COALESCE(count(*), 0) as clicks, 
    COALESCE(hour(time), hour(now())) as hour 
FROM 
    clicks 
WHERE DATE(time) = DATE(NOW()) GROUP BY hour

Hope that's what you're looking for.