Count and select all dates for a specific field in MySQL

Question

i have a data format like this:

+----+--------+---------------------+
| ID | utente | data                |
+----+--------+---------------------+
| 1  | Man1   | 2014-02-10 12:12:00 |
+----+--------+---------------------+
| 2  | Women1 | 2015-02-10 12:12:00 |
+----+--------+---------------------+
| 3  | Man2   | 2016-02-10 12:12:00 |
+----+--------+---------------------+
| 4  | Women1 | 2014-03-10 12:12:00 |
+----+--------+---------------------+
| 5  | Man1   | 2014-04-10 12:12:00 |
+----+--------+---------------------+
| 6  | Women1 | 2014-02-10 12:12:00 |
+----+--------+---------------------+

I want to make a report that organise the ouptout in way like this:

+---------+--------+-------+---------------------+---------------------+---------------------+
| IDs     | utente | count | data1               | data2               | data3               |
+---------+--------+-------+---------------------+---------------------+---------------------+
| 1, 5    | Man1   | 2     | 2014-02-10 12:12:00 | 2014-04-10 12:12:00 |                     |
+---------+--------+-------+---------------------+---------------------+---------------------+
| 2, 4, 6 | Women1 | 3     | 2015-02-10 12:12:00 | 2014-03-10 12:12:00 | 2014-05-10 12:12:00 |
+---------+--------+-------+---------------------+---------------------+---------------------+

All the row thath include the same user (utente) more than one time will be included in one row with all the dates and the count of records. Thanks

Answer 1

While it's certainly possible to write a query that returns the data in the format you want, I would suggest you to use a GROUP BY query and two GROUP_CONCAT aggregate functions:

SELECT
  GROUP_CONCAT(ID) as IDs,
  utente,
  COUNT(*) as cnt,
  GROUP_CONCAT(data ORDER BY data) AS Dates
FROM
  tablename
GROUP BY
  utente

then at the application level you can split your Dates field to multiple columns.

Answer 2

Looks like a fairly standard "Breaking" report, complicated only by the fact that your dates extend horizontally instead of down...

SELECT * FROM t ORDER BY utente, data
$lastutente = $lastdata = '';
echo "<table>\n";
while ($row = fetch()) {
    if ($lastutente != $row['utente']) {
        if ($lastutente != '') {
            /****
             * THIS SECTION REF'D BELOW
             ***/
            echo "<td>$cnt</td>\n";
            foreach ($datelst[] as $d) 
                echo "<td>$row[data]</td>\n";
            for ($i = count($datelst); $i < $NumberOfDateCells; $i++)
                echo "<td>&nbsp;</td>\n";
            echo "</tr>\n";
            /****
             * END OF SECTION REF'D BELOW
             ***/
        }
        echo "<tr><td>$row[utente]</td>\n"; // start a new row - you probably want to print other stuff too
        $datelst = array();
        $cnt = 0;
    }
    if ($lastdata != $row['data']) {
        datelst[] = $row['data'];
    }
    $cnt += $row['cnt']; // or $cnt++ if it's one per row
}
print the end of the last row - see SECTION REF'D ABOVE
echo "</table>\n";

You could add a GROUP BY utente, data to your query above to put a little more load on mysql and a little less on your code - then you should have SUM(cnt) as cnt or COUNT(*) as cnt .