Question

I have a table with data in a following format

region   gender  age_group  population 

Dallas    M        1          200  
Dallas    F        1          500 
NY        M        1          320 
NY        F        1          310 
Dallas    M        2          300 
Dallas    F        2          600 
NY        M        2          400 
NY        F        2          800 

I’m looking for the best query to output my data in the following format

region/age_group      1           2
Gender             M     F       M    F
Dallas             200   500    300  600
NY                 320   310    400  800

my query returns only the top colum and region. Not sure how to sub divide the top colum into genders as appearing above

SELECT distinct (region), a.group_one, b.group_two 
FROM city_populations c  
LEFT JOIN city_populations AS a ON a.age_group=1 AND c.age_group=a.age_group  
LEFT JOIN city_populations AS b ON b.age_group=2 AND c.age_group=a.age_group  

Answer 1

//First i fetched all data from database

$result = mysql_query("select * from test2")or die(mysql_error());
$regions = array();
$age_groups = array();
while($det = mysql_fetch_array($result)){

    if(!in_array($det['region'], $regions)){
        $regions[] = $det['region'];
    }
    if(!in_array($det['age_group'], $age_groups)){
        $age_groups[] = $det['age_group'];
    }
    $rows[] = $det;
}

//then processed in php to show as you wanted

echo "<table>";
echo "<tr><td>Age group</td>";
foreach($age_groups as $keyAG => $valueAG){
    echo "<td colspan='2'>$valueAG</td>";
}
echo "</tr>";
echo "<tr><td>Gender</td>";
foreach($age_groups as $keyAG => $valueAG){
    echo "<td>M</td>";
    echo "<td>F</td>";
}
echo "</tr>";
foreach($regions as $keyR => $valueR){

    echo "<tr>";
    echo "<td>".$valueR."</td>";
    foreach($age_groups as $keyAG => $valueAG){

        foreach($rows as $keyROWS => $valueROWS){
            if($valueROWS['region'] == $valueR && $valueROWS['age_group'] == $valueAG){
                if($valueROWS['gender'] == 'M'){
                    echo "<td>".$valueROWS['population']."</td>";
                }
                elseif($valueROWS['gender'] == 'F'){
                    echo "<td>".$valueROWS['population']."</td>";
                }
            }
        }
        $data[$valueR][$valueAG] = array($maleValue, $femaleValue);

    }
    echo "</tr>";
}
echo "</table>";

Note: It is highly recommended to use mysqli_* instead of mysql.