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I'm having a small issue with my code. What I want to do is show the results of a select as json. This is how I do it:

foreach ($query as $row) {
    $test = json_encode($row);
}

But it returns that:

{0: "34.8", 1: "1441098255", 2: "1", col1: "34.8", col2: "1441098255", col3: "1"}

And I want it like this:

{0: "34.8", 1: "1441098255", 2: "1"}

Or this:

{col1: "34.8", col2: "1441098255", col3: "1"}

I tried doing what they say here, but to no avail.

Edit: The replies are helpful, and they do what I want. The problem now is that I have some sneaky part that for some reason can't seem to get rid of. Here's the resulting json string:

{"col1":"34.8","0":"34.8","col2":"1441098255","col3":"1"}

That "0":"34.8" seems to not want to leave, and I have absolutely no idea where it comes from, and if I change the column order, it always duplicates whatever column comes first. If I put "col3" as the first one, it displays this:

{"col3":"1","0":"1","col2":"1441098255","col1":"34.8"}

Edit2: Turns out the solution was much simpler than what I tried. Here's how to display it properly:

while ($arr = $query->fetch(PDO::FETCH_ASSOC)) {
    echo json_encode($arr);
}
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7
  • 1
    you can easily build the right format in your loop for the desired output then after the loop output the array in json Commented Apr 13, 2017 at 10:55
  • @Gert Do you mind explaining how to do that? Commented Apr 13, 2017 at 10:57
  • 1
    It looks like you've got a database result indexed both by numeric IDs and column names - you should be able to specify which you want when fetching the result (in the call to PDOStatement::fetch or similar). You haven't included your database code though, so it's impossible to say exactly what you'd need to change. Commented Apr 13, 2017 at 10:59
  • @iainn you mean the select? I use $query = $this->dbh->prepare(select stuff...) followed by $query->execute(); Commented Apr 13, 2017 at 11:04
  • what is the json data being used for example mobile app to connect to DB ? @Newwt Commented Apr 13, 2017 at 11:06

3 Answers 3

Reset to default
2

Use array_filter with ARRAY_FILTER_USE_KEY flag

$keys = ["col1", "col2", "col3"];
foreach ($query as $row) {
    $filtered = array_filter((Array) $row, function($key) use($keys) {
        return in_array($key, $keys);
    }, ARRAY_FILTER_USE_KEY);
    $test = json_encode($filtered);
}

Notice: If your $row is array not object you don't need to cast it to array (Array) $row

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8 Comments

I get Call to undefined function array_fiter()
@Newwt its literal mistake should be filter
mother of god, and I didn't even notice it haha! It does exactly what I wanted it to do, thank you!
@Newwt i guess from different place because $query = [["col1"=>"x",1=>"y"]]; returns filtered
to be honest you should follow @iainn idea, how comes you get both numeric and associative keys in array?
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0

You can use array_chunk to get the first three element of $row.

json_encode(array_chunk($row, 3, true)[0]);
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2 Comments

why not array_slice($row, 0, 3)
This returns something weird with the json: {"col1":"34.8","0":"34.8","col2":"1441098255"}. Edit: I just noticed it does the same with the answer I marked as "solved". hm.
0 
 $data=array();
foreach ($query as $row) {

   $data[]=$row;
   //$test = json_encode($row);
}

$test = json_encode( $data);
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1 Comment

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