How to compare two mysql tables in php

Databases
1

i have a movie table and i want to compare the common movies of two users.


$array1=array();
$array2=array();
$query2="select name from movie where user_id='1'";
$result2=mysql_query($query2) or die(mysql_error());
while($rss = mysql_fetch_assoc ($result2))
{
    $array1[]=$rss;
}
print_r($array1);

This will print

Array ( [0] => Array ( [name] => Snatch ) [1] => Array ( [name] => The Social Network Movie )<br />[2] => Array ( [name] => Death Note ) [3] => Array ( [name] => Titanic ) <br />[4] => Array ( [name] => Once Upon a Time in the West ) )

And for second user

$query3="select name from movie where user_id=1";
$result3=  mysql_query($query3) or die(mysql_error());
while($rss1=  mysql_fetch_assoc($result3))
{
    $array2[]=$rss1;
}
print_r($array2);

This will print

Array ( [0] => Array ( [name] => The Lord of the Rings Trilogy ) [1] => Array ( [name] => Snatch ) <br />[2] => Array ( [name] => The Social Network Movie ) [3] => Array ( [name] => Scarface ) <br />[4] => Array ( [name] => Once Upon a Time in the West ) [5] => Array ( [name] => Legend of the Guardians: The Owls of Ga'Hoole ) [6] => Array ( [name] => Once Upon a Time in America ) <br />[7] => Array ( [name] => Butch Cassidy and the Sundance Kid ) [8] => Array ( [name] => Fracture ) <br />[9] => Array ( [name] => Invictus ) [10] => Array ( [name] => Pride and Glory ) [11] => Array ( [name] => Casablanca ) )

When i compare these two arrays it gives me the first array.

$match= array_intersect($array1, $array2);
print_r($match);

The result will is

Array ( [0] => Array ( [name] => Snatch ) [1] => Array ( [name] => The Social Network Movie )<br />[2] => Array ( [name] => Death Note ) [3] => Array ( [name] => Titanic ) <br />[4] => Array ( [name] => Once Upon a Time in the West ) )

But the Common movies are:

 Snatch , The social network movie , once upon a time in the west
2

You would be better performing this filtering in MySQL. My SQL isn’t the best, but assuming each user can only add the same movie name once, this may do it:-


SELECT
    name
  , COUNT(name) AS occurrences
FROM
  movie
WHERE
  user_id IN (1, 2)
GROUP BY
  name HAVING(occurrences) > 1
3

HAVING(occurrences) > 1 should be HAVING occurrences > 1

the (unnecessary (proliferation) of (parentheses) is unnecessary)

:smiley:

4

Ha, thanks Rudy.

I seem to remember you chastising me for doing the same with DISTINCT a year or so ago. :slight_smile: