Question

I have a MySQL Database That Looks like This:

Name: Joe
Items: 25
CreationDate: 2012-04-14 18:49:50

Name: John
Items: 89
CreationDate: 2012-04-14 18:47:17

Name: Bill
Items: 95
CreationDate: 2012-04-09 12:34:08

Name: Bob
Items: 35
CreationDate: 2012-04-09 12:18:23

What I want to do is group the rows by CreationDate (Based on only the day, the time at the end should not be a factor). And Then Add the Items Together to come up with an Items / Day.

So I want the output to be something like this:

2012-04-09 - 130 items
2012-04-14 - 114 items

I’ve tried the Group By in MySQL but I’m not sure if i’m using it right:

$sql = mysql_query("SELECT SUM(Items), CreationDate FROM People GROUP BY CreationDate ORDER BY CreationDate DESC") or die(mysql_error());
while($row = mysql_fetch_array($sql) ) {
    echo '<p>' . $row['CreationDate'] . ' - ' . $row['SUM(Items)'] . '</p>';
}

That kind of works except it Groups them only on exact match Creation Date (Down to the second) and i’m not sure how to fix for that.

Answer 1

You need to use the date-function for the CreationDate field, such as:

SELECT SUM(Items), DATE(CreationDate) FROM People GROUP BY DATE(CreationDate) ORDER BY CreationDate DESC

A warning though: Using the DATE-function will ignore any index on the CreationDate. If the CreationDate-field is indexed, using the DATE-function and grouping on it will take much longer time.