php mysql check previous row - php

Question

I have output from a select query as below
id price valid
1000368 69.95 1
1000369 69.94 0
1000370 69.95 0
now in php I am trying to pass the id 1000369 in function. the funciton can execute only if the valid =1 for id 1000368. if it's not 1 then it will throw error. so if the id passed is 1000370, it will check if valid =1 for 1000369.
how can i check this? I think it is logically possible to do but I am not able to code it i tried using foreach but at the end it always checks the last record 1000370 and so it throws error.
regards

Answer 1

Use a boolean variable:
<?php
$lastValid=false;
while($row = mysql_fetch_array($result))
{
if ($lastValid) {
myFunction();
}
$lastValid = $row['valid'];
}
?>
(Excuse possible errors, have no access to a console at the moment.)

Answer 2

If I understand correctly you want to check the if the previous id is valid.
$prev['valid'] = 0;
foreach($input as $i){
if($prev['valid']){
// Execute function
}
$prev = $i;
}

Answer 3

<?php
$sql = "SELECT * FROM tablename";
$qry = mysql_query($sql);
while($row = mysql_fetch_array($qry))
{
if ($row['valid'] == 1)
{
// do some actions
}
}
?>

Answer 4

I really really recommend walking through some tutorials. This is basic stuff man.
Here is how to request a specific record:
//This is to inspect a specific record
$id = '1000369'; //**some specified value**
$sql = "SELECT * FROM data_tbl WHERE id = $id";
$data = mysql_fetch_assoc(mysql_query($sql));
$valid = $data['valid'];
if ($valid == 1)
//Do this
else
//Do that
And here is how to loop through all the records and check each.
//This is to loop through all of it.
$sql = "SELECT * FROM data_tbl";
$res = mysql_query($sql);
$previous_row = null;
while ($row = mysql_fetch_assoc($res))
{
some_action($row, $previous_row);
$previous_row = $row; //At the end of the call the current row becomes the previous one. This way you can refer to it in the next iteration through the loop
}
function some_action($data, $previous_data)
{
if (!empty($previous_data) && $condition_is_met)
{
//Use previous data
$valid = $previous_data['valid'];
}
else
{
//Use data
$valid = $data['valid'];
}
if ($valid == 1)
{
//Do the valid thing
}
else
{
//Do the not valid thing
}
//Do whatever
}
Here are some links to some good tutorials:
http://www.phpfreaks.com/tutorials
http://php.net/manual/en/tutorial.php