PHP Comparing Values From While Loop Outside Of Loop - php

Question

I'm trying to find the best way to compare dates outside a while statement. I wrote a function and set the while loop inside. Taking in account that I need to compare every single date from the loop with $this_new_date, how can I achieve this?
function getDates(){
$returnDates = array();
while($result = mysqli_fetch_array($allDatesQuery)){
$returnDates[] = date("Y-n-j",strtotime($result['date']));
}}
if($returnDates===$this_new_date){
//do something here
}

Answer 1

Please note that if you are going to use the MySQLi extension (http://php.net/manual/en/book.mysqli.php) you will need to use a while loop to store your data unless you are running PHP >= 5.3 in which case you can use mysqli_fetch_all (http://php.net/mysqli_fetch_all).
Option 1
Perform the date comparison inside the query. This is going to be your absolute best/fastest option. That way PHP does not even need to do anything.
Example:
SELECT * FROM table WHERE date = ?;
Then use a prepared statement to pass your date value to the query: http://php.net/manual/en/mysqli.quickstart.prepared-statements.php
Option 2
Assuming you need to perform this date comparison in PHP the while loop is still going to be the fastest because unless the date you're looking for is the very last record you can likely get away without having to read the entire query result.
function is_date_in_query($this_new_date, $allDatesQuery) {
while($result = mysqli_fetch_array($allDatesQuery)) {
if (strtotime($this_new_date) == strtotime($result['date'])) {
return TRUE;
}
}
return FALSE;
}
if (is_date_in_query($this_new_date, $allDatesQuery)) {
// yes the date is inside - do something
}
else {
// no the date is not inside - do something else
}
But you say you cannot use a while loop so let's look at another option.
Option 3
Use a combination of mysqli_fetch_all, in_array and array_column. This prevents any while loops but requires you to load the entire query result.
Example:
// Put ALL rows into an array
$result_array = mysqli_fetch_all($allDatesQuery, MYSQLI_ASSOC);
// Check if the date is anywhere in the result array
if (in_array(date('Y-m-d', strtotime($this_new_date)), array_column($result_array, 'date'))) {
// yes the date is inside - do something
}
else {
// no the date is not inside - do something else
}
Here is a working example (updated): https://eval.in/868105

Answer 2

you could do something like this:
...
$matchedDates = array_filter($returnDates, function($value) use($this_new_date){
return $value == $this_new_date;
});
var_dump($matchedDates);