通过复选框选择，通过PHP将MySQL表导出为CSV

The initial result set needs to be wrapped in a form which POST to the next page. The Checkbox must send an array of ids to the export script.

<input type='checkbox' name='xport[]' value='ID_OF_THE_ROW_HERE'>

The [ ] after xport means that $_POST['xport'] will be an array of values.

The export page can collapse that array of ids into a comma separated string and to be used the query:

SELECT * FROM results WHERE id IN (4,7,11,30)

<form method="POST" action="downloadcsv.php">

        <h1>PEEM Results List</h1>
        <a class="exportCSV" href="https://domain.com/downloadcsv.php">Export to CSV</a>
        <!-- Export CSV button -->
        <h3 class="resultsbydate">All results by date</h3>


            <div class="resultsListHeader">
                <div class="clientidTab">Agency</div>
                <div class="clientidTab">Family ID</div>
                <div class="clientidName">Name</div>
                <div class="clientidTab">Date</div>
                <div class="clientidTab"></div>
            </div>
            <div class="entriesListMain">
                <?php
                $connection = mysql_connect("localhost", "username", "password"); // Establishing Connection with Server
                $db = mysql_select_db("database_name", $connection); // Selecting Database
                //MySQL Query to read data
                $query = mysql_query("select * from results ORDER BY peemdate DESC", $connection);
                while ($row = mysql_fetch_array($query)) {
                echo "<div><input type='checkbox' name='xport[]' value='{$row['client_id']}'><span>{$row['client_id']}</span> <span>{$row['family_id']}</span> <span>{$row['firstname']} {$row['lastname']}</span> <span>".date("d F Y", strtotime($row['peemdate']))."</span>";
                echo "<span><a class=\"parents-button\" href=\"peem-parent-repsonses.php?id={$row['survey_id']}\"><strong>Parent&rsquo;s Review</strong></a></span>";
                echo "<span><a href=\"peem-repsonses.php?id={$row['survey_id']}\"><strong>View Results</strong></a></span>";
                echo "</div>";
                }
                ?>
            </div>

         </form>

Change $row['client_id'] to the correct value

Then in the export script:

<?php
/*
Expecting $_POST['xport'] array of row ids
*/
if( !isset($_POST['xport']) OR !is_array($_POST['xport']) ) {
    exit('No rows selected for export');
}

$conn = mysql_connect("localhost","username","password");
mysql_select_db("databasename",$conn);

$filename = "peem_results.csv";
$fp = fopen('php://output', 'w');

$query = "SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA='realwell_peemfinal' AND TABLE_NAME='results'";
$result = mysql_query($query);
while ($row = mysql_fetch_row($result)) {
    $header[] = $row[0];
}   

header('Content-type: application/csv');
header('Content-Disposition: attachment; filename='.$filename);
fputcsv($fp, $header);

//Cast all ids to integer
$ids = $_POST['xport'];
array_walk($ids, function(&$value, $key) {
    $value = (int)$value;
});

$ids = implode(', ', $ids);

$query = "SELECT * FROM results WHERE id IN ($ids)";
$result = mysql_query($query);
while($row = mysql_fetch_row($result)) {
    fputcsv($fp, $row);
}
exit;
?>

So if I'm getting this correctly, you just need to be able to check checkboxes to select the databses ($rows) you want to insert into the csv file....

Every checkbox that you checked will be in the $_POST variable, so:

1st you make an array with all the names of checkbox options (databases), for example

$all_db = ['database1', 'database2', 'database3'];

2nd you loop through each of the values in $all_db and check if they exist in the $_POST array, if they do, then you can export the row

foreach( $all_db as $db_check ) {
     if ( array_key_exists( $db_check, $_POST ) {
          // EXPORT TO CSV
      }
 }

Don't forget ! This means the "name" attribute of the checkbox should be the name of the database.

If you don't want to have a static list of databases (i.e. there is a possibillity of them having different names in the future / there will be moreor maybe less etc then let me know i can edit my answer if needed :) )

( If you use the $_GET variable, then you can do the same thing just change $_POST to $_GET)

Know though that $_GET comes over as a bit amateuristic for the enduser if he gets a thousand variables in his URL,

$_POST is often a better alternative since it is hidden and cleaner for the enduser...

EDIT: UPDATING ANSWER (SEE COMMENT)

So basically you need people to be able to choose what rows they export from you dB... First of all this means we need a unique ID for each row,

This can either be a column used solely for that (i.e. ID column with auto increment and unique attribute) Or this can be a column you already have, just make sure it's a unique column so we don't get dupliate values (you'll see why below)

Then we give the value of this unique ID column to the checkbox's "name" attribute, and using jquery / php we append / prepend a static string...

For example, using your family ID: "rownumber_" + $family_ID

This gets us (again using your example) : $_POST[] = ['rownumber_123456' => 1, 'rownumber_0000000' => 1, .....]

So then in your PHP file you just do the following to add the correct lines to your CSV:

 while($row = mysql_fetch_row($result)) {
      if ( array_key_exists($row['your_row_id'], $_POST) {
           fputcsv($fp, $row);
      }
 }

-- Again using your example with family_ID : --

 while($row = mysql_fetch_row($result)) {
      if ( array_key_exists($row['family_ID'], $_POST) {
           fputcsv($fp, $row);
      }
 }

EDIT: Updating answer for comment no.2

So little sidenote if you are going to loop through html using php (i.e. loop trhough db rows and print them out in an orderly fashion) Then you propably want to use the ":" variants of the loops,

• While() :
• for() :
• foreach() :
• if () :
• .....

These variants allow yu to close the php tag after the ":" and whataver html / css / php / jquery you put in the condition / loop will be executed like normal...

For example you can do :

 <ul>
 <?php foreach ($row as $columnkey => $columnvalue): ?>
      <img src="whateveryouwant"?>
      <li class="<?php echo $columnkey;?>">This is my value: <?php echo $columnvalue; ?></li>
 <?php endforeach; ?>
 </ul>

When you do it this way it's much cleaner and you won't have any problems using double quatation signs and all that stuff :)

So using that method here is how your displayed list would look like in code:

    <div class="entriesListMain">
    <?php
                $connection = mysql_connect("localhost", "username", "password"); // Establishing Connection with Server
                $db = mysql_select_db("database_name", $connection); // Selecting Database
                //MySQL Query to read data
                $query = mysql_query("select * from results ORDER BY peemdate DESC", $connection);
                while ($row = mysql_fetch_array($query)) : 
    ?>


                  <div>
                      <input type="checkbox" name="<?php echo $row['family_id']; ?>" value="export">
                      <span><?php echo $row['client_id']; ?></span> 
                      <span><?php echo $row['family_id']; ?></span> 
                      <span><?php echo $row['firstname'] . " " . $row['lastname']; ?></span> 
                      <span><?php echo date("d F Y",strtotime($row['peemdate']); ?></span>;
                      <span>
                        <a class="parents-button" href="peem-parent-repsonses.php?id=<?php echo $row['survey_id']; ?>">
                        <strong>Parent&rsquo;s Review</strong>
                        </a>
                      </span>
                      <span>
                        <a href="peem-repsonses.php?id=<?php echo $row['survey_id']; ?>">
                        <strong>View Results</strong>
                        </a>
                      </span>
                    </div>


                <?php endwhile; ?>
 </div>

Like this the checkbox will get the name of the family ID, and so in your csv.php you can use this code :

  while($row = mysql_fetch_row($result)) {
       if ( array_key_exists($row['family_ID'], $_POST) {
            fputcsv($fp, $row);
       }
  }

Since now it will check for each row wether the family ID of the SQL row is posted as a wanted row in the $_POST variable (checkbooxes) and if not it won't export the row into the csv file ! :)

So there you go ^^

EDIT 3: Troubleshooting

So there are a couple of things that you do in this function, the form, Do the checkboxes in your html form have the family_ID in their name attribute ? (i.e. <input type="checkbox" name="<?php echo $row['family_id']; ?>".... check if the name attribute is really filled )

you post stuff from a form, (your checkboxes and stuff)so let's see what actually gets posted,

die(print_r($_POST)); - This means you want php to die after this line (stop working at all), then print out a variable as is (sort of xml format you'll see)

So then you will get a whole bunch of information, if you want to see this information in a nicely formated way, just right click inspect element on it :)

Then see how your checkboxes are coming out of the $_POST variable, (they should have the family_ID as a key and a value of 1)

If that's all ok, then check your row['family_ID'] variable see if the family_ID is filled correctly, do the same with your whole $row variable, in fact check every variable you use in csv.php and then check why the key does not exist in the array you are searching for :)

Also dont forget to check that you filled the array_key_exists( has a key FIRST and an array[] LAST )

I can't help you directly with this , since this will propably be a faulty variable or a mistake in your form so try to find this yourself, if still nothing , post these variables values:

• $_POST
• $row
• and the full HTML of your form