php – Row count with PDO

The Question :

203 people think this question is useful

There are many conflicting statements around. What is the best way to get the row count using PDO in PHP? Before using PDO, I just simply used mysql_num_rows.

fetchAll is something I won’t want because I may sometimes be dealing with large datasets, so not good for my use.

Do you have any suggestions?

The Question Comments :

The Answer 1

278 people think this answer is useful
$sql = "SELECT count(*) FROM `table` WHERE foo = ?"; 
$result = $con->prepare($sql); 
$result->execute([$bar]); 
$number_of_rows = $result->fetchColumn(); 

Not the most elegant way to do it, plus it involves an extra query.

PDO has PDOStatement::rowCount(), which apparently does not work in MySql. What a pain.

From the PDO Doc:

For most databases, PDOStatement::rowCount() does not return the number of rows affected by a SELECT statement. Instead, use PDO::query() to issue a SELECT COUNT(*) statement with the same predicates as your intended SELECT statement, then use PDOStatement::fetchColumn() to retrieve the number of rows that will be returned. Your application can then perform the correct action.

EDIT: The above code example uses a prepared statement, which is in many cases is probably unnecessary for the purpose of counting rows, so:

$nRows = $pdo->query('select count(*) from blah')->fetchColumn(); 
echo $nRows;

The Answer 2

87 people think this answer is useful

As I wrote previously in an answer to a similar question, the only reason mysql_num_rows() worked is because it was internally fetching all the rows to give you that information, even if it didn’t seem like it to you.

So in PDO, your options are:

  1. Use PDO’s fetchAll() function to fetch all the rows into an array, then use count() on it.
  2. Do an extra query to SELECT COUNT(*), as karim79 suggested.
  3. Use MySQL’s FOUND_ROWS() function UNLESS the query had SQL_CALC_FOUND_ROWS or a LIMIT clause (in which case the number of rows that were returned by the query and the number returned by FOUND_ROWS() may differ). However, this function is deprecated and will be removed in the future.

The Answer 3

33 people think this answer is useful

As it often happens, this question is confusing as hell. People are coming here having two different tasks in mind:

  1. They need to know how many rows in the table
  2. They need to know whether a query returned any rows

That’s two absolutely different tasks that have nothing in common and cannot be solved by the same function. Ironically, for neither of them the actual PDOStatement::rowCount() function has to be used.

Let’s see why

Counting rows in the table

Before using PDO I just simply used mysql_num_rows().

Means you already did it wrong. Using mysql_num_rows() or rowCount() to count the number of rows in the table is a real disaster in terms of consuming the server resources. A database has to read all the rows from the disk, consume the memory on the database server, then send all this heap of data to PHP, consuming PHP process’ memory as well, burdening your server with absolute no reason.
Besides, selecting rows only to count them simply makes no sense. A count(*) query has to be run instead. The database will count the records out of the index, without reading the actual rows and then only one row returned.

For this purpose the code suggested in the accepted answer is fair, save for the fact it won’t be an “extra” query but the only query to run.

Counting the number rows returned.

The second use case is not as disastrous as rather pointless: in case you need to know whether your query returned any data, you always have the data itself!

Say, if you are selecting only one row. All right, you can use the fetched row as a flag:

$stmt->execute();
$row = $stmt->fetch();
if (!$row) { // here! as simple as that
    echo 'No data found';
}

In case you need to get many rows, then you can use fetchAll().

fetchAll() is something I won’t want as I may sometimes be dealing with large datasets

Yes of course, for the first use case it would be twice as bad. But as we learned already, just don’t select the rows only to count them, neither with rowCount() nor fetchAll().

But in case you are going to actually use the rows selected, there is nothing wrong in using fetchAll(). Remember that in a web application you should never select a huge amount of rows. Only rows that will be actually used on a web page should be selected, hence you’ve got to use LIMIT, WHERE or a similar clause in your SQL. And for such a moderate amount of data it’s all right to use fetchAll(). And again, just use this function’s result in the condition:

$stmt->execute();
$data = $stmt->fetchAll();
if (!$data) { // again, no rowCount() is needed!
    echo 'No data found';
}

And of course it will be absolute madness to run an extra query only to tell whether your other query returned any rows, as it suggested in the two top answers.

Counting the number of rows in a large resultset

In such a rare case when you need to select a real huge amount of rows (in a console application for example), you have to use an unbuffered query, in order to reduce the amount of memory used. But this is the actual case when rowCount() won’t be available, thus there is no use for this function as well.

Hence, that’s the only use case when you may possibly need to run an extra query, in case you’d need to know a close estimate for the number of rows selected.

The Answer 4

21 people think this answer is useful

This is super late, but I ran into the problem and I do this:

function countAll($table){
   $dbh = dbConnect();
   $sql = "select * from `$table`";

   $stmt = $dbh->prepare($sql);
    try { $stmt->execute();}
    catch(PDOException $e){echo $e->getMessage();}

return $stmt->rowCount();

It’s really simple, and easy. 🙂

The Answer 5

19 people think this answer is useful

I ended up using this:

$result = $db->query($query)->fetchAll();

if (count($result) > 0) {
    foreach ($result as $row) {
        echo $row['blah'] . '<br />';
    }
} else {
    echo "<p>Nothing matched your query.</p>";
}

The Answer 6

13 people think this answer is useful

This post is old but Getting row count in php with PDO is simple

$stmt = $db->query('SELECT * FROM table');
$row_count = $stmt->rowCount();

The Answer 7

6 people think this answer is useful

This is an old post, but getting frustrated looking for alternatives. It is super unfortunate that PDO lacks this feature, especially as PHP and MySQL tend to go hand in hand.

There is an unfortunate flaw in using fetchColumn() as you can no longer use that result set (effectively) as the fetchColumn() moves the needle to the next row. So for example, if you have a result similar to

  1. Fruit->Banana
  2. Fruit->Apple
  3. Fruit->Orange

If you use fetchColumn() you can find out that there are 3 fruits returned, but if you now loop through the result, you only have two columns, The price of fetchColumn() is the loss of the first column of results just to find out how many rows were returned. That leads to sloppy coding, and totally error ridden results if implemented.

So now, using fetchColumn() you have to implement and entirely new call and MySQL query just to get a fresh working result set. (which hopefully hasn’t changed since your last query), I know, unlikely, but it can happen. Also, the overhead of dual queries on all row count validation. Which for this example is small, but parsing 2 million rows on a joined query, not a pleasant price to pay.

I love PHP and support everyone involved in its development as well as the community at large using PHP on a daily basis, but really hope this is addressed in future releases. This is ‘really’ my only complaint with PHP PDO, which otherwise is a great class.

The Answer 8

3 people think this answer is useful

Answering this because I trapped myself with it by now knowing this and maybe it will be useful.

Keep in mind that you cant fetch results twice. You have to save fetch result into array, get row count by count($array), and output results with foreach. For example:

$query = "your_query_here";
$STH = $DBH->prepare($query);
$STH->execute();
$rows = $STH->fetchAll();
//all your results is in $rows array
$STH->setFetchMode(PDO::FETCH_ASSOC);           
if (count($rows) > 0) {             
    foreach ($rows as $row) {
        //output your rows
    }                       
}

The Answer 9

2 people think this answer is useful

Have a look at this link: http://php.net/manual/en/pdostatement.rowcount.php It is not recommended to use rowCount() in SELECT statements!

The Answer 10

1 people think this answer is useful

If you just want to get a count of rows (not the data) ie. using COUNT(*) in a prepared statement then all you need to do is retrieve the result and read the value:

$sql = "SELECT count(*) FROM `table` WHERE foo = bar";
$statement = $con->prepare($sql); 
$statement->execute(); 
$count = $statement->fetch(PDO::FETCH_NUM); // Return array indexed by column number
return reset($count); // Resets array cursor and returns first value (the count)

Actually retrieving all the rows (data) to perform a simple count is a waste of resources. If the result set is large your server may choke on it.

The Answer 11

1 people think this answer is useful

To use variables within a query you have to use bindValue() or bindParam(). And do not concatenate the variables with " . $variable . "

$statement = "SELECT count(account_id) FROM account
                  WHERE email = ? AND is_email_confirmed;";
$preparedStatement = $this->postgreSqlHandler->prepare($statement);
$preparedStatement->bindValue(1, $account->getEmail());
$preparedStatement->execute();
$numberRows= $preparedStatement->fetchColumn();

GL

The Answer 12

0 people think this answer is useful

When it is matter of mysql how to count or get how many rows in a table with PHP PDO I use this

// count total number of rows
$query = "SELECT COUNT(*) as total_rows FROM sometable";
$stmt = $con->prepare($query);

// execute query
$stmt->execute();

// get total rows
$row = $stmt->fetch(PDO::FETCH_ASSOC);
$total_rows = $row['total_rows'];

credits goes to Mike @ codeofaninja.com

The Answer 13

-1 people think this answer is useful

A quick one liner to get the first entry returned. This is nice for very basic queries.

<?php
$count = current($db->query("select count(*) from table")->fetch());
?>

Reference

The Answer 14

-1 people think this answer is useful

I tried $count = $stmt->rowCount(); with Oracle 11.2 and it did not work. I decided to used a for loop as show below.

   $count =  "";
    $stmt =  $conn->prepare($sql);
    $stmt->execute();
   echo "<table border='1'>\n";
   while($row = $stmt->fetch(PDO::FETCH_OBJ)) {
        $count++;
        echo "<tr>\n";
    foreach ($row as $item) {
    echo "<td class='td2'>".($item !== null ? htmlentities($item, ENT_QUOTES):"&amp;nbsp;")."</td>\n";
        } //foreach ends
        }// while ends
        echo "</table>\n";
       //echo " no of rows : ". oci_num_rows($stmt);
       //equivalent in pdo::prepare statement
       echo "no.of rows :".$count;

The Answer 15

-1 people think this answer is useful

For straight queries where I want a specific row, and want to know if it was found, I use something like:

function fetchSpecificRow(&amp;$myRecord) {
    $myRecord = array();
    $myQuery = "some sql...";
    $stmt = $this->prepare($myQuery);
    $stmt->execute(array($parm1, $parm2, ...));
    if ($myRecord = $stmt->fetch(PDO::FETCH_ASSOC)) return 0;
    return $myErrNum;
}

The Answer 16

-1 people think this answer is useful

There is a simple solution. If you use PDO connect to your DB like this:

try {
    $handler = new PDO('mysql:host=localhost;dbname=name_of_your_db', 'your_login', 'your_password'); 
    $handler -> setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} 
    catch (PDOException $e) {   
    echo $e->getMessage();
}

Then, the query to DB will be:

$query = $handler->query("SELECT id FROM your_table WHERE ...");

And finally, to count the rows matching your query write like this

$amountOfRows = $query->rowcount();

The Answer 17

-1 people think this answer is useful

fetchColumn()

used if want to get count of record [effisien]

$sql   = "SELECT COUNT(*) FROM fruit WHERE calories > 100";
$res   = $conn->query($sql);
$count = $res->fetchColumn(); // ex = 2

query()

used if want to retrieve data and count of record [options]

$sql = "SELECT * FROM fruit WHERE calories > 100";
$res = $conn->query($sql);

if ( $res->rowCount() > 0) {

    foreach ( $res as $row ) {
        print "Name: {$row['NAME']} <br />";
    }

}
else {
    print "No rows matched the query.";
}

PDOStatement::rowCount

The Answer 18

-2 people think this answer is useful

when you make a COUNT(*) in your mysql statement like in

$q = $db->query("SELECT COUNT(*) FROM ...");

your mysql query is already counting the number of result why counting again in php? to get the result of your mysql

$q = $db->query("SELECT COUNT(*) as counted FROM ...");
$nb = $q->fetch(PDO::FETCH_OBJ);
$nb = $nb->counted;

and $nb will contain the integer you have counted with your mysql statement a bit long to write but fast to execute

Edit: sorry for the wrong post but as some example show query with count in, I was suggesting using the mysql result, but if you don’t use the count in sql fetchAll() is efficient, if you save the result in a variable you won’t loose a line.

$data = $dbh->query("SELECT * FROM ...");
$table = $data->fetchAll(PDO::FETCH_OBJ);

count($table) will return the number of row and you can still use the result after like $row = $table[0] or using a foreach

foreach($table as $row){
  print $row->id;
}

The Answer 19

-2 people think this answer is useful

Here’s a custom-made extension of the PDO class, with a helper function to retrieve the number of rows included by the last query’s “WHERE” criteria.

You may need to add more ‘handlers’, though, depending on what commands you use. Right now it only works for queries that use “FROM ” or “UPDATE “.

class PDO_V extends PDO
{
    private $lastQuery = null;

    public function query($query)
    {
        $this->lastQuery = $query;    
        return parent::query($query);
    }
    public function getLastQueryRowCount()
    {
        $lastQuery = $this->lastQuery;
        $commandBeforeTableName = null;
        if (strpos($lastQuery, 'FROM') !== false)
            $commandBeforeTableName = 'FROM';
        if (strpos($lastQuery, 'UPDATE') !== false)
            $commandBeforeTableName = 'UPDATE';

        $after = substr($lastQuery, strpos($lastQuery, $commandBeforeTableName) + (strlen($commandBeforeTableName) + 1));
        $table = substr($after, 0, strpos($after, ' '));

        $wherePart = substr($lastQuery, strpos($lastQuery, 'WHERE'));

        $result = parent::query("SELECT COUNT(*) FROM $table " . $wherePart);
        if ($result == null)
            return 0;
        return $result->fetchColumn();
    }
}

The Answer 20

-2 people think this answer is useful

You can combine the best method into one line or function, and have the new query auto-generated for you:

function getRowCount($q){ 
    global $db;
    return $db->query(preg_replace('/SELECT [A-Za-z,]+ FROM /i','SELECT count(*) FROM ',$q))->fetchColumn();
}

$numRows = getRowCount($query);

The Answer 21

-2 people think this answer is useful
<table>
      <thead>
           <tr>
                <th>Sn.</th>
                <th>Name</th>
           </tr>
      </thead>
      <tbody>
<?php
     $i=0;
     $statement = $db->prepare("SELECT * FROM tbl_user ORDER BY name ASC");
     $statement->execute();
     $result = $statement->fetchColumn();
     foreach($result as $row) {
        $i++;
    ?>  
      <tr>
         <td><?php echo $i; ?></td>
         <td><?php echo $row['name']; ?></td>
      </tr>
     <?php
          }
     ?>
     </tbody>
</table>

The Answer 22

-2 people think this answer is useful
function count_x($connect) {  
 $query = "  SELECT * FROM tbl WHERE id = '0' ";  
 $statement = $connect->prepare($query);  $statement->execute();  
 $total_rows = $statement->rowCount();  
 return $total_rows; 
}

The Answer 23

-4 people think this answer is useful

Use parameter array(PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL), else show -1:

Usen parametro array(PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL), sin ello sale -1

example:

$res1 = $mdb2->prepare("SELECT clave FROM $tb WHERE id_usuario='$username' AND activo=1 and id_tipo_usuario='4'", array(PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL));
$res1->execute();

$count=$res1->rowCount();
echo $count;

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