Aplicado ao seu caso, aqui está a resposta de Danny adaptada. :
<?php
//first query:
$arrk = array_keys($_POST['overtimehours']);
$arrv = array_values($_POST['overtimehours']);
$id_list = implode(',', $arrk);
$whens = implode(
"\n ",
array_map(
function ($id, $value) {
return "WHEN {$id} THEN {$value}";
},
$arrk,
$arrv
)
);
$sql1 = "
UPDATE $TABLE
SET ot_hours = CASE trans_num
{$whens}
END,
ot_status=1,
ot_submitdate='$ot_submitdate'
WHERE id IN ({$id_list})
AND uid='$contextUser'
AND (ot_status=0 OR ot_status=1 OR ot_status=3)
";
//second query:
$arrk = array_keys($_POST['lieutimehours']);
$arrv = array_values($_POST['lieutimehours']);
$id_list = implode(',', $arrk);
$whens = implode(
"\n ",
array_map(
function ($id, $value) {
return "WHEN {$id} THEN {$value}";
},
$arrk,
$arrv
)
);
$sql2 = "
UPDATE $TABLE
SET lieu_hours = CASE trans_num
{$whens}
END,
ot_status=1,
ot_submitdate='$ot_submitdate'
WHERE id IN ({$id_list})
AND uid='$contextUser'
AND (ot_status=0 OR ot_status=1 OR ot_status=3)
";
//now use pdo to run sql1 and sql2
?>