PHP PostgreSQL array to string

Question

I have a problem in my PHP script that uses PostgreSQL for fetching and storing data.

Currently I am using the following code:

 $q = "SELECT id FROM playlisty WHERE id_profilu=1;";
 $r = pg_query($q);
 $arr = pg_fetch_all($r);
 echo '<pre>'; var_dump($arr); echo'</pre>';

The output generated by the above code snippet:

array(4) {
 [0]=>
 array(1) {
 ["id"]=>
 string(4) "2014"
 }
 [1]=>
 array(1) {
 ["id"]=>
 string(4) "1549"
 }
 [2]=>
 array(1) {
 ["id"]=>
 string(4) "1965"
 }
 [3]=>
 array(1) {
 ["id"]=>
 string(4) "2047"
 }
}

However, I would prefer if the output looked something like the following: 2014, 1549, 1965, 2047 (i.e. a simple array of id-s of certain playlists). I also tried using implode (to no anvil), and got Array,Array,Array,Array as a reply.

Answer 1

Why not just loop it ?

$str=""; 
foreach($yourarr as $arr) 
{ 
 $str.=implode(',',$arr).',';
} 
echo rtrim($str,','); //"prints" 2014, 1549, 1965, 2047

• M.Stark: When i loop it can i use it in "SELECT * FROM table WHERE id IN ($str)" ?
• Shankar Narayana Damodaran: I don't have an idea what results that query would return...By the way did you try the code which I gave you ?
• M.Stark: Yes, for me the result is "2014154919652047" - as You can see there is no commas
• M.Stark: $q = "SELECT id FROM playlisty WHERE id_profilu=1 "; $r = pg_query($q); $yourarr = pg_fetch_all($r); $str=""; foreach($yourarr as $arr) { $str.=implode(',',$arr); } echo $str

Answer 2

Add this line before echo:

$arr = array_map(function ($v) { return $v['id']; }, $arr);

If you want to output result as string then you have to use implode function. Replace last line with this:

echo '<pre>'. implode(', ', $arr). '</pre>';

• M.Stark: it returned "array(4) { [0]=> string(4) "2014" [1]=> string(4) "1549" [2]=> string(4) "1965" [3]=> string(4) "2047" }"
• hindmost: If you want to output result as string you have to use implode function (php.net/manual/en/function.implode.php) instead of var_dump: echo '<pre>'; implode(', ', $arr); echo'</pre>';

Answer 3

Try this:

$array = array(
 0=>array('id'=>"2014"),
 1=>array('id'=>"2015"),
 2=>array('id'=>"2016"),
 );
 $ids = array_map(function($item) { return $item['id']; }, $array);
 $result = implode($ids,',');
 var_dump($result);

Output: string '2014,2015,2016' (length=14)

Answer 4

Do select like this:

$q = "SELECT array_to_string(id, ',') AS id FROM playlisty WHERE id_profilu=1 ";

• M.Stark: and how do i get the result from this ?
• Vin.AI: Like this: $arr[0]['id'] will return 2014,2015,2016[,...]. You don't have need to implode using php.