2 columns on a left join - php

Question

Hello so I have 2 tables. tbl_records and tbl_guards. On tbl_guards I have guard_id and on tbl_records I have guard_id and guard_id_in. And here is my current code:
try
{
$stat = "0";
$query = "SELECT rec.*, tbl_guard.fname, tbl_guard.lname
FROM tbl_records as rec
LEFT JOIN tbl_guard ON tbl_guard.guard_id = rec.guard_id
LEFT JOIN tbl_records ON tbl_records.guard_id_in = tbl_guard.guard_id
WHERE rec.stud_id=? AND rec.status=?";
$stmt = $dbc->prepare($query);
$stmt->bindParam(1, $_GET['id']);
$stmt->bindParam(2, $stat);
$stmt->execute();
echo "<table cellpadding='3' class='searchTbl'>";
echo "<thead>";
echo "<tr>";
echo "<th>Actual Date</th>";
echo "<th>Purpose</th>";
echo "<th>Destination</th>";
echo "<th>Exact TO</th>";
echo "<th>Expected TI</th>";
echo "<th>Guard</th>";
echo "<th>Actual TI</th>";
echo "<th>Guard IN</th>";
echo "</tr>";
echo "</thead>";
while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
extract($row);
$guard = $fname . " " . $lname;
echo "<tbody>";
echo "<tr>";
echo "<td>$act_date</td>";
echo "<td>$purpose</td>";
echo "<td>$destination</td>";
echo "<td>$exact_timeout</td>";
echo "<td>$exp_timein</td>";
echo "<td>$guard</td>";
echo "<td>$act_timein</td>";
echo "<td>$guard</td>";
echo "</tr>";
echo "</tbody>";
}
}
catch (PDOException $e)
{
echo "Error: " . $e->getMessage();
}
echo "</table>";
Here is tbl_records data.
And here is tbl_guard data.
Here is the current output.
My problem is it shows the same guard in guard_id and guard_id_in in my code.

Answer 1

You can use LEFT JOIN multiple times, like:
SELECT tbl_records.*, tbl_guard.fname, tbl_guard.lname
FROM tbl_records as rec
LEFT JOIN tbl_guard ON tbl_guard.guard_id = rec.guard_id
LEFT JOIN tbl_records ON tbl_records.guard_id_in = tbl_guard.guard_id

Answer 2

You can use:
SELECT tbl_records.*, tbl_guard.fname, tbl_guard.lname
FROM tbl_records
LEFT JOIN tbl_guard ON (tbl_records.guard_id OR tbl_records.guard_id_in) = tbl_guard.guard_id

Answer 3

You should select twice the guard table and use aliases for your fields :
SELECT tr1.*, tg1.fname AS FNAME, tg1.lname AS LNAME,
tg2.fname AS FNAME_IN, tg2.lname AS LNAME_IN
FROM tbl_records AS tr1
LEFT JOIN tbl_guard AS tg1
ON tg1.guard_id = tr1.guard_id,
LEFT JOIN tbl_guard AS tg2
ON tg2.guard_id = trl.guard_id_in
then in PHP you'll have more vars : $FNAME, $LNAME, $FNAME_IN, $LNAME_IN

Answer 4

Just to be sure, your tbl_records table can have a link to two different tbl_guards via guard_id and guard_id_in ?
Maybe you can try :
SELECT tbl_records.*, tbl_guard.fname, tbl_guard.lname FROM tbl_records LEFT JOIN tbl_guard ON tbl_guard.guard_id IN (tbl_records.guard_id, tbl_records.guard_id_in)

Answer 5

SELECT tr1.*, tg1.fname, tg2.lname
FROM tbl_records AS tr1
LEFT JOIN tbl_guard AS tg1 ON tg1.guard_id = tr1.guard_id,
LEFT JOIN tbl_guard AS tg2 ON tg2.guard_id = trl.guard_id_in