MySQL: filling empty fields with zeroes when using GROUP BY

Question

I\'ve got MySQL table

CREATE TABLE cms_webstat (
    ID int NOT NULL auto_increment PRIMARY KEY,
    TIMESTAMP_X timestamp DEFAULT CURRENT_TIMESTAMP,
    # .         


        

Answer 1

Create another table with a single column,

CREATE TABLE hours_list (
    hour int NOT NULL PRIMARY KEY
)

Fill it with all 24 hours.

Then do a join on that table to fill in the zeroes.

SELECT
    hs.hour as HOUR, COUNT(ws.ID) AS HOUR_STAT
FROM hours_list hs 
LEFT JOIN cms_webstat ws ON hs.hour = hour(ws.TIMESTAMP_X)
GROUP BY hs.hour
ORDER BY hs.hour DESC