MySQL计数包括不在日期范围内的月份

Question

Supposed I have a table that contains the following table:

+----+-----------+---------+-------------------------+
| id |  item     |  ....   | dateLogged              |
+----+-----------+---------+-------------------------+
|  1 | 2015-001  |  ....   | 2015-06-01 12:09:00     |
|  2 | 2015-001  |  ....   | 2015-06-01 12:09:00     |
|  3 | 2015-002  |  ....   | 2015-06-30 15:40:02     |
|  4 | 2015-002  |  ....   | 2015-06-30 15:40:03     |
|  5 | 2015-003  |  ....   | 2015-07-02 13:38:22     |
+----+-----------+---------+-------------------------+

I want to search the number of items based on the year, month and count from the dateLogged, with the expected data:

+--------+----------+----------------+
| year   |  month   |     total      | 
+--------+----------+----------------+
|  2015  | January  |      0         | 
|  2015  | February |      0         | 
|  2015  | March    |      0         | 
|  2015  | April    |      0         | 
|  2015  | May      |      0         | 
|  2015  | June     |      4         | 
|  2015  | July     |      1         | 
|  2015  | August   |      0         | 
|  2015  | September|      0         | 
|  2015  | October  |      0         | 
|  2015  | November |      0         | 
|  2015  | December |      0         |
+--------+----------+----------------+

But I am only getting this based on the following SQL:

SELECT DATE_FORMAT(dateLogged, '%Y') as 'year', MONTHNAME(dateLogged) 
as 'month', COUNT(id) as 'total' from item a where dateLogged >= '2015-06-29 00:00:00' 
and dateLogged <= '2015-07-02 23:59:59' 
GROUP BY DATE_FORMAT(a.dateLogged, '%Y%m');

+--------+---------+----------------+
| year   |  month  |  No of items   | 
+--------+---------+----------------+
|  2015  | June    |      4         | 
|  2015  | July    |      1         | 
+----+-------------+----------------+    

I've tried searching elsewhere from stackoverflow, but wasn't able to get any answers, or probably have missed. Wanna know if there is any solution to this, thanks.

I am using Java to compute this, so any suggestions using Java to compute the above is also welcomed.

Answer 1

You could change your query to return the 0 values as well using loops to iterate over months and years and then find the count. Something like this:

Map<String, Integer> values = new HashMap<String, Integer>();
for(int year = 2015; year < 2017; year++)
{
    for(int month = 1; month <= 12; month++)
    {
        rs = stmt.executeQuery("SELECT COUNT(id) as 'total' from item where
                 MONTH(dateLogged) = " + month + " and YEAR(dateLogged) = " + year + ";";
        rs.next();
        int count = rs.getInt("total");
        String time = Integer.toString(year) + "-" + Integer.toString(month);
        values.Add(time, count);
    }
}

This would return you a map like this:

values['2015-1'] = 0;
values['2015-2'] = 0; 

.. and so on.

Of course, you could store the returned count with year and month however you want, depending on how you wish to use it further.

Answer 2

One idea is to, somehow, create a calendar table, and use it, so that you get a row for each month of year 2015:

SELECT DATE_FORMAT(m, '%Y') as 'year', 
       MONTHNAME(m) as 'month',
       COUNT(id) as 'total' 
FROM (SELECT '2015-01-01' AS m UNION ALL SELECT '2015-02-01' UNION ALL
      SELECT '2015-03-01' UNION ALL SELECT '2015-04-01' UNION ALL 
      SELECT '2015-05-01' UNION ALL SELECT '2015-06-01' UNION ALL 
      SELECT '2015-07-01' UNION ALL SELECT '2015-01-08' UNION ALL 
      SELECT '2015-09-01' UNION ALL SELECT '2015-10-01' UNION ALL 
      SELECT '2015-11-01' UNION ALL SELECT '2015-12-01') AS x
LEFT JOIN item a 
ON DATE_FORMAT(a.dateLogged, '%Y%m') = DATE_FORMAT(x.m, '%Y%m') 
   AND dateLogged >= '2015-06-29 00:00:00' 
   AND dateLogged <= '2015-07-02 23:59:59' 
GROUP BY DATE_FORMAT(x.m, '%Y%m');

The above query makes use of sort of an inline calendar table for year 2015. This table is used as a basis in the FROM clause, so that the query returns a row for each of the months of year 2015.

Demo here