Count/group rows based on date including missing - mysql

Question

I have a bunch of rows in my db that signify orders, i.e.
id | date
---------------------
1 | 2013-09-01
2 | 2013-09-01
3 | 2013-09-02
4 | 2013-09-04
5 | 2013-09-04
What I'd like is to display the count of rows per day, including missing days, so the output would be:
2013-09-01 | 2
2013-09-02 | 1
2013-09-03 | 0
2013-09-04 | 2
I've seen examples of having 2 tables, one with the records and the other with dates, but I'd ideally like to have a single table for this.
I can currently find the rows that have a record, but not days that do not.
Does anyone have a n idea on how to do this?
Thanks

Answer 1

If you want to get data for last 7 days, you can generate your pseudo-table via UNION, like:
SELECT
COUNT(t.id),
fixed_days.fixed_date
FROM t
RIGHT JOIN
(SELECT CURDATE() as fixed_date
UNION ALL SELECT CURDATE() - INTERVAL 1 day
UNION ALL SELECT CURDATE() - INTERVAL 2 day
UNION ALL SELECT CURDATE() - INTERVAL 3 day
UNION ALL SELECT CURDATE() - INTERVAL 4 day
UNION ALL SELECT CURDATE() - INTERVAL 5 day
UNION ALL SELECT CURDATE() - INTERVAL 6 day) AS fixed_days
ON t.`date` = `fixed_days`.`fixed_date`
GROUP BY
`fixed_days`.`fixed_date`
-see this fiddle demo. Note, that if your fields are DATETIME date type, then you'll need to applyy DATE() first:
SELECT
COUNT(t.id),
fixed_days.fixed_date
FROM t
RIGHT JOIN
(SELECT CURDATE() as fixed_date
UNION ALL SELECT CURDATE() - INTERVAL 1 day
UNION ALL SELECT CURDATE() - INTERVAL 2 day
UNION ALL SELECT CURDATE() - INTERVAL 3 day
UNION ALL SELECT CURDATE() - INTERVAL 4 day
UNION ALL SELECT CURDATE() - INTERVAL 5 day
UNION ALL SELECT CURDATE() - INTERVAL 6 day) AS fixed_days
ON DATE(t.`date`) = `fixed_days`.`fixed_date`
GROUP BY
`fixed_days`.`fixed_date`

Answer 2

Try Something like this!
SELECT
c1,
GROUP_CONCAT(c2 ORDER BY c2) AS 'C2 values'
FROM table
GROUP BY c1;
To retrieve a list of c1 values for which there exist specific values in another column c2, you need an IN clause specifying the c2 values and a HAVING clause specifying the required number of different items in the list ...
SELECT c1
FROM table
WHERE c2 IN (1,2,3,4)
GROUP BY c1
HAVING COUNT(DISTINCT c2)=4;
For more help by this related question
Counting all rows with specific columns and grouping by week

Answer 3

Use the following stored procedure it will allow you to get results for more than 7 days, just pass the number of days you want
DELIMITER $$
CREATE DEFINER=`server`#`%` PROCEDURE `test`(d INT)
BEGIN
CREATE TEMPORARY TABLE dates
(
f_day DATETIME
);
WHILE d > 0 DO
INSERT INTO dates SELECT DATE(NOW())-d;
SET d = d - 1;
END WHILE;
SELECT
IF(isnull(`id`),0,`id`),
`fixed_days`.`f_day`
FROM t
RIGHT JOIN
dates AS `fixed_days`
ON t.`date` = `fixed_days`.`f_day`
GROUP BY
`fixed_days`.`f_day`;
DROP TABLE dates;
END