Question

Until recently I’ve been using mysql_real_escape_string() to fix most of my variables before making SQL queries to my database. A friend said that I should be using PDO’s prepared statements instead, so after reading a bit about them I’m now switching over to them.

I’ve only encountered one problem so far in switching over, and that’s counting the rows to returned by a SELECT statement. On occasion in my code, I’d run an SQL query and then count the number of rows returned from the SELECT statement. Depending on whether a result set returned, I would take different actions. Sometimes I do need to use the result set from it. MySQL let me go straight to mysql_fetch_assoc() after mysql_num_rows() with no problem. However, PDO doesn’t seem to have anything like mysql_num_rows().

I’ve been reading some responses on SO that gave me a solution, to either use COUNT() in the SQL statement or to use the PHP function count() on the result set. COUNT() would work fine in the SQL statement if I didn’t need the result set in some places, however, several people have mentioned that using count() on the result set is fairly inefficient.

So my question is, how should I be doing this if I need to count the number of rows selected (if any), then run a script with the result set? Is using count() on the result set the only way in this case, or is there a more efficient way to do things?

Below is a short example of something similar to my previous SQL code:

$query=mysql_query('SELECT ID FROM Table WHERE Name='Paul' LIMIT 1);

if(mysql_num_rows($query)>0)
{
  print_r(mysql_fetch_assoc($query));
}
else
{
  //Other code.
}

Thanks.

EDIT

I do know that you use fetchAll() on the statement before counting the result set (which gives me what I need), but I’m just trying to figure out the most efficient way to do things.

Answer 1

$stmt->rowCount();

http://php.net/manual/en/pdostatement.rowcount.php

the rows must be fetched(buffered into memory, or iterated) for it to work. It’s not uncommon for your pdo driver to be configured to do this automatically.