Retrieving data from DB in PHP using foreach

Question

I have a sql to select all the row that matches with the user_id. Then I store that into an array using $dataFromDB = $stmtA->fetchAll();

Array
(
    [0] => Array
        (
            [0] => 55
            [1] => 7
            [2] => temperature
            [3] => 1
            [4] => 19
            [5] => 35
            [6] => 2015-11-26 14:41:34
        )
    [1] => Array
        (
            [0] => 56
            [1] => 7
            [2] => humidity
            [3] => 1
            [4] => 37
            [5] => 57
            [6] => 2015-11-26 14:42:36
        )
)

The problem is that using a foreach as this:

foreach( $dataFromDB as $k => $row ){
    $json_response['SS'] = $row[2];
    $json_response['MN'] = $row[4];
    $json_response['MX'] = $row[5];
}

Only get:

[SS] => humidity
[MM] => 37
[MX] => 57

And I would like to receive

[SS] => temperature, humidity
[MM] => 19, 37
[MX] => 35, 57

How could I do to store both of then [0] and [1] into an array and then show them? I think the problem is in the foreach, and my goal is to save into a multidimensional array [][], where I can access using for example, $json_response[1][1] to the value of the second array (MM) and the second value.

Niranjan N Raju · Accepted Answer · 2015-11-26 16:39:55Z

2

try like this,

$ss = $mn = $mx = "";
foreach( $dataFromDB as $k => $row ){
    $ss .= $row[2];
    $mn .= $row[4];
    $mx .= $row[5];
}

$json_response['SS'] = rtrim($ss,",");
$json_response['MN'] = rtrim($mn,",");
$json_response['MX'] = rtrim($mx,",");

Instead of looping it, you can get data directly in query from database. Something like this

GROUP_CONCAT(table_name.column_name SEPARATOR ', ')

and use GROUP BY.

answered Nov 26, 2015 at 16:39

Niranjan N Raju

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4 Comments

Niranjan N Raju Over a year ago

but if you can get comma separated values directly from query, no need to use loops.

CapAm Over a year ago

Thanks, mate, I'm going to try to change the query to see what I received. If not I'll try the loop

Niranjan N Raju Over a year ago

i would say, first finish with the loops, then try with query.

Niranjan N Raju Over a year ago

and consider the answer if it was helpful:)

Steve · Accepted Answer · 2015-11-26 16:46:03Z

1

You are currently overwriting the values. Instead add them as seperate array elements:

//initialize with empty arrays
$json_response=['SS'=>[], 'MN'=>[], 'MX'=>[]];

foreach( $dataFromDB as $k => $row ){
    $json_response['SS'][] = $row[2];
    $json_response['MN'][] = $row[4];
    $json_response['MX'][] = $row[5];
}

This will produce the multidimentional array you mention in your last paragraph (not the comma separated values you show above it).

If you wanted the comma seperated values instead, you can implode the arrays after:

foreach($json_response as &$val)
    $val = implode(',', $val);

edited Nov 26, 2015 at 16:46

answered Nov 26, 2015 at 16:40

Steve

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