trying to do if post meta !=0

get_post_meta($id, 'key', true)

• returns string if the key exists
• return false if the key doesn't exists

If you're using wp-postratings or any other plugin that uses custom_fields, they don't create the key until it is used, so you can save time doing:

if(!get_post_meta()) {
    // when field doesn't exist (false) or the value is integer 0 or empty string ''
} else {
    // when the field exists
}

I appreciate all the answers but $post_id was the issue it should have been $post->ID

<?php if(get_post_meta( $post->ID, 'ratings_users', true ) =='0' ) {
}else{
the_ratings();
} ?>

Based on your clarification, I would recommend something like the following:

<?php 
$rating = get_post_meta( $post_id, 'ratings_users', true );

if ( '0' < $rating ) {
    the_ratings();
}
?>

Alternately, you could use:

<?php 
$rating = get_post_meta( $post_id, 'ratings_users', true );

if ( '' != $rating && '0' != $rating ) {
    the_ratings();
}
?>

But I think the first method will work; and is more concise.

The important thing to note here is that get_post_meta() returns an empty string if the post meta value isn't set.

To extand Marc Duncans (a.k.a. @t31os) answer:

You multiple ways to question "if ( $some_val_A IS $some_val_B )". There is a difference between equal and identical.

$real_world_ex = get_post_meta( $post_id, 'ratings_users', true );

// Example: test this in your functions.php
function wpse26016_test_vars( $real_world_ex = '' )
{
    $some_int = (int) 1;
    $some_bool = (bool) 1;
    $some_string = (string) 1;

    echo '<pre>';
        echo 'I\'m an integer: ';
            var_dump( $some_int );
        echo '<br />I\'m some boolean: ';
            var_dump( $some_bool );
        echo '<br />I\'m some string: ';
            var_dump( $some_string );

    echo '<hr><strong>Now we can see some comparison<strong><br />';
        echo '<br />I test if integer is <em>equal</em> boolean (notice the 2 "="-signs): ';
            var_dump( $some_int == $some_bool );
        echo '<br />I test if integer is <em>identical</em> boolean (notice the 3 "="-signs): ';
            var_dump( $some_int === $some_bool );
        echo '<br />I test if integer is <em>not equal</em> boolean: ';
            var_dump( $some_int != $some_bool );
        echo '<br />I test if integer is <em>not identical</em> boolean: ';
            var_dump( $some_int !== $some_bool );

    echo '<hr><strong>Now some real world example<strong><br />';
        echo '<br />This is the dump of what's inside your meta data: ';
            var_dump( $real_world_ex );

        echo '<br />I test if integer is <em>equal</em> to your meta data: ';
            var_dump( $some_int == $real_world_ex );
        echo '<br />I test if integer is <em>identical</em> to your meta data: ';
            var_dump( $some_int === $real_world_ex );

        echo '<br />I test if boolean is <em>equal</em> to your meta data: ';
            var_dump( $some_bool == $real_world_ex );
        echo '<br />I test if boolean is <em>identical</em> to your meta data: ';
            var_dump( $some_bool === $real_world_ex );

        echo '<br />I test if string is <em>equal</em> to your meta data: ';
            var_dump( $some_string == $real_world_ex );
        echo '<br />I test if string is <em>identical</em> to your meta data: ';
            var_dump( $some_string === $real_world_ex );
    echo '<pre>';
}

As you can see (when you paste wpse26016_test_vars() in your template), there's a difference between comparing "against value" or type "against value and type".

Use this function always to see if you're doing it right :)

The reason you have a problem is 0 is also considered equal to false, when the get_post_meta call returns false, it's also the same as being equal to 0.

if( !get_post_meta( $post_id, 'some-non-existant-field', true ) == 0 )

Would be the same as ...

if( get_post_meta( $post_id, 'some-existing-field', true ) == 0 )

..the only difference is in one case the field doesn't exist, and in one it does(and has a zero value), both will be true though.

Additionally, 0 is not the same as '0', ie. one is a string value, the other an actual numeric value. Custom field values are stored as strings, so your comparison should go along the lines of..

if( get_post_meta( $post_id, 'some-existing-field', true ) == '0' )

.. to be accurate.

I realise i'm bad at explaining this, so i hope that helps(or someone else explains it better).

Try this:

if ( get_post_meta( $post_id, 'ratings_users', true ) != 0 ) {
    the_ratings();
} else {
    // Do nothing here
}