根据表的一列对MySQL查询的结果进行分组

Question

I have the following query:

if ($stmt = $mysqli->prepare("SELECT Date, Due, Paid from patient_sessions WHERE Name=? AND Invoiced=? AND Type=? AND SUBSTR(Date,1,7)=? ORDER BY Date")) {

    $stmt->bind_param("ssss",$client,$invoiced,$type,$month);
    $stmt->execute();
    $stmt->store_result();
    $stmt->bind_result($date,$due,$paid);

while ($stmt->fetch()) {

RUN SOMETHING HERE

}

Rather than use while ($stmt->fetch()) , which loops through all of the rows returned, I would like to group the rows returned by the value in the Due column, and then loop through each row per group, but I am not sure how to do this.

EXTRA INFO

I would like to return the results in the following format:

One line for each 'Due' value returned with a count of the number of rows for each value (this is what the grouping is needed for).

And then...

One line for each row, ordered by date where all of the 3 values (Date,Due,Paid) are displayed.

I am stuck because I need the grouping and also the individual rows. Can I return both with the one query?

Answer 1

$sql = "SELECT Date, Due, Paid from patient_sessions 
        WHERE Name=? AND Invoiced=? AND Type=? AND SUBSTR(Date,1,7)=? 
        ORDER BY Due, Date";
$stmt = $mysqli->prepare($sql);
$stmt->bind_param("ssss",$client,$invoiced,$type,$month);
$stmt->execute();
$stmt->store_result();
$stmt->bind_result($date,$due,$paid);
$data = array();
while ($stmt->fetch())
{
    if (!isset($data[$due]))
    {
         $data[$due] = array();
    }
    $data[$due][] = array($date,$paid);
}
print_r($data);

Answer 2

Have a look at 'Group By' and 'Having' clauses.

Will need more information to give you a real answer but hopefully these links will help.

http://www.w3schools.com/sql/sql_having.asp