Echo array based on distinct key - php

Question

I have “ordered by” a database to be in ascending country order, then descending years. Each database record contains: countryname, year, details. There are many duplicate countries, but the years are different. For instance:
Albania, 2000, details
Albania, 1965, details
Croatia, 2014, details
Croatia, 2003, details
Can’t figure out how to echo the array to get results like the following where country is on one line and years & details are listed below without duplicating the name of the country:
Albania
2000, details
1965, details
Croatia
2014, details
2003, details
Seems like I need foreach distinct country, echo year and details?
Here is my php so far:
$result = mysql_query("SELECT country, year, details FROM studies ORDER BY country, year DESC ");
//output data from each row in db
while($row = mysql_fetch_array($result)) {
echo " Country: " .$row['country']. "<br /> Year: " .$row['year']. " Details: ".$row['details']. "<br /><br /> ";
}
Would appreciate any help, I'm stumped!

Answer 1

Try adding a country check:
$newcountry = '';
while($row = mysql_fetch_array($result)) {
if ($newcountry != $row['country']) {
echo "Country:". $row['country']."<br />";
$newcountry = $row['country'];
}
echo " Year: " .$row['year']. " Details: ".$row['details']. "<br /><br /> ";
}
This should work, because you have ordered your query by Country. This is critical, otherwise you should absolutely add a GROUP BY clause to your SQL.
EDIT: to add a <div> around the group, you simply would change the echo sequence, checking first to see if the country has already been set once. It would look like:
$newcountry = 'undefined';
while($row = mysql_fetch_array($result)) {
if ($newcountry !='undefined' && $newcountry != $row['country']){
echo '</div>'; // only add a closing div if a new country (and not 1st)
}
if ($newcountry != $row['country']) {
echo "Country:". $row['country']."<br /><div class='countryDetail'>";
$newcountry = $row['country'];
}// added the start of the <div>
echo " Year: " .$row['year']. " Details: ".$row['details']. "<br /><br /> ";
}
if ($newcountry != 'undefined') { //make sure at least one <div> is set
echo "</div>"; // close the last <div>
}
I added the class countryDetail to the div, so you can use this with toggle in your jQuery.

Answer 2

You can use nested while loops. You might also want to use PDO/mysqli_ functions/prepared statements in place of mysql_ functions:
// get unique country list first
$sql1 = "SELECT DISTINCT(country) FROM studies ORDER BY country";
$result1 = mysql_query($sql1);
// iterate through result set of sql1
while($row1 = mysql_fetch_array($result1))
{
$country = $row1['country'];
echo "<br>"; // new line
echo $country;
// get year, details for each country
$sql2 = "SELECT year, details FROM studies WHERE country = '$country' ORDER BY year DESC";
$result2 = mysql_query($sql2);
// iterate through result set of $sql2
while ($row2 = mysql_fetch_array($result2))
{
echo "<br>"; // new line
echo $row2['year']. ", " . $row2['details'];
}
}

Answer 3

loop party!
$rows = [];
while($row = mysql_fetch_array($result)) {
$rows[ $row['country'] ] = [ $row['year'], $row['details'] ];
}
foreach($rows as $country => $row) {
$details = array_map(function($items) { return sprintf("\t - %s: %s\n", $items[0], $items[1]) }, $row);
echo sprintf("\n%s:\n %s", $country, $details);
}