Creating JSON from multiple PHP arrays

Question

I have created three arrays in a PHP file, all of which got their elements from a MYSQL database. Even though I have used the json_encode method to prepare the arrays, the results is not parsable JSON.

I am very new to JSON and PHP, but I have tried to encode the three arrays into one variable, as well as three different variable. But in both situations when I echo the result, it is not valid JSON.

I created the arrays in the beginning of the PHP file.

$physicianArr = array();

$patientArr = array();

$apmtArr = array();

I used this general method to populate all of the arrays (lines are used for breaking the three examples, not included in code.)

if (mysqli_num_rows($resultPhysician) > 0) {
  while($row=mysqli_fetch_assoc($resultPhysician)) {
    $physicianArr[] = $row;
  }
  $physicianJSON = json_encode($physicianArr);
}

if (mysqli_num_rows($resultPatient) > 0) {
  while($row=mysqli_fetch_assoc($resultPatient)) {
    $patientArr[] = $row;
  }
  $patientJSON = json_encode($patientArr);
}

if (mysqli_num_rows($resultApmt) > 0) {
  while($row=mysqli_fetch_assoc($resultApmt)) {
    $apmtArr[] = $row;
  }
  $apmtJSON = json_encode($apmtArr);
}

RESULTS:

the when I type in the url to retrieve this PHP file on a web browser here is the result, three separate arrays instead of one JSON:

[
    {"UserID":"3","FirstName":"Jane","LastName":"Parkey"}, 
    {"UserID":"4","FirstName":"Jamie","LastName":"Crane"},
    {"UserID":"5","FirstName":"Jerry","LastName":"Martin"},
    {"UserID":"6","FirstName":"Alexander","LastName":"Dollar"},
    {"UserID":"8","FirstName":"Bob","LastName":"Loblaw"},
    {"UserID":"11","FirstName":"Mary","LastName":"Robbins"},
    {"UserID":"15","FirstName":"testy","LastName":"testy"}
][
    {"UserID":"1","FirstName":"Joe","LastName":"Smith"},
    {"UserID":"2","FirstName":"Adam","LastName":"Stone"},
    {"UserID":"9","FirstName":"Michael","LastName":"Jordan"},
    {"UserID":"10","FirstName":"Tom","LastName":"Holland"},
    {"UserID":"12","FirstName":"test1","LastName":"test1"},
    {"UserID":"19","FirstName":"Will","LastName":"Smith"},
    {"UserID":"20","FirstName":"Joe","LastName":"Imburgia"}
][
    {"apmtID":"1","PhysicianID":"15","apmtDate":"Jun 26, 2019","apmtTime":"09:00:00 AM","PatientID":"1"},
    {"apmtID":"2","PhysicianID":"15","apmtDate":"test","apmtTime":"test","PatientID":"1"},
    {"apmtID":"4","PhysicianID":"15","apmtDate":"Apr 20, 2019","apmtTime":"7:10:36 AM","PatientID":"1"}
]

Answer 1

Here is a suggestion. If you want one data structure then only echo one.

// make sure all arrays exist
$physicianArr   = [];
$patientArr     = [];
$apmtArr        = [];

if (mysqli_num_rows($resultPhysician) > 0) {
    while($row=mysqli_fetch_assoc($resultPhysician)) {
        $physicianArr[] = $row;
    }
}   

if (mysqli_num_rows($resultPatient) > 0) {
    while($row=mysqli_fetch_assoc($resultPatient)) {
        $patientArr[] = $row;
    }
}

if (mysqli_num_rows($resultApmt) > 0) {
    while($row=mysqli_fetch_assoc($resultApmt)) {
        $apmtArr[] = $row;
    }
}

echo json_encode( 
                [
                    'Physicians'    => $physicianArr
                    'Patients'      => $patientArr
                    'Ampt'          => $apmtArr
                ] 
            );

Answer 2

you can use the function array_merge so that your arrays are combined into one. once you do this, you can use json_encode function to encode this one array that holds all the data from the three arrays.