PHP: Merging arrays with the same title - php

Question

I have some php arrays from a loop, all of them bearing the same name. Now I want to merge them, but it seems not to work...
Here's my loop:
while($row = mysql_fetch_row($sql1)){
$startzeit=strtotime($row[2]);
$endzeit=strtotime($row[3]);
$startzeit_format = date("Y-m-d",$startzeit);
$endzeit_format = date("Y-m-d",$endzeit);
$datearray[] = createDateRangeArray($startzeit_format,$endzeit_format);
}
This should be the merging code:
for($i = 0; $i<count($datearray); $i++)
{
$datesarray = array_merge($datearray[$i]);
}
Anyway, the manual merge works fine:
$datesarray = array_merge( $datearray[0], $datearray[1], $datearray[2], $datearray[3]);
This one leads to the desired output. However I'd like to automatize it, as the single arrays come from a database and I won't add a $datearray[4], $datearray[5] and so on, everytime there is a new entry in the mySQL..
The result of print_r($datearray):
Array (
[0] => Array ( [0] => 2014-03-08 )
[1] => Array ( [0] => 2013-09-15 )
[2] => Array ( [0] => 2013-09-21 )
[3] => Array ( [0] => 2013-10-03
[1] => 2013-10-04
[2] => 2013-10-05
[3] => 2013-10-06 )
)

Answer 1

What you might be looking for is to flatten the array:
$datesarray = call_user_func_array('array_merge', $datearray);
It's identical to how you were manually merging together the array items.
See also: call_user_func_array()
You could also do this inside the loop with a simple loop:
$datesarray = array();
while ($row = mysql_fetch_row($sql1)) {
// ...
foreach (createDateRangeArray($startzeit_format,$endzeit_format) as $item) {
$datesarray[] = $item;
}
}

Answer 2

You are merging a single array to nothing.
$newArray = array_merge($array, $array)
Merges those two arrays but you are doing
$array = array_merge($datearray[$i]);
In affect, you are creating an array from one key of an array.