Wordpress - what is the correct way to compare dates in a WP query_posts meta_query

I wound up working on the exact same thing and this post was very helpful. I used Custom Fields and here is the code that I used to create a list of all events greater than the current date. Note the extra taxonomy based filters.

<?php // Let's get the data we need to loop through below

$events = new WP_Query( 
    array(
        'post_type' => 'event', // Tell WordPress which post type we want
        'orderby' => 'meta_value', // We want to organize the events by date    
        'meta_key' => 'event-start-date', // Grab the "start date" field created via "More Fields" plugin (stored in YYYY-MM-DD format)
        'order' => 'ASC', // ASC is the other option    
        'posts_per_page' => '-1', // Let's show them all.   
        'meta_query' => array( // WordPress has all the results, now, return only the events after today's date
            array(
                'key' => 'event-start-date', // Check the start date field
                'value' => date("Y-m-d"), // Set today's date (note the similar format)
                'compare' => '>=', // Return the ones greater than today's date
                'type' => 'DATE' // Let WordPress know we're working with date
                )
            ),
        'tax_query' => array( // Return only concerts (event-types) and events where "songs-of-ascent" is performing
            array(
                'taxonomy' => 'event-types',
                'field' => 'slug',
                'terms' => 'concert',
                ),
            array(
                'taxonomy' => 'speakers',
                'field' => 'slug',
                'terms' => 'songs-of-ascent',
                )
            )
        )
    );
?>

It largely depends on how your date is stored in the meta value in the first place. In general, it is a good idea to store dates in MySQL as MySQL dates/timestamps.

MySQL timestamps have the format Y-m-d h:i:s.

However, it is always a good idea to use WP's own date mangling functions. As such, to get the current date in MySQL format, use current_time('mysql').

To format a MySQL date for display, use mysql2date($format, $mysql_date). In this case it is best to display the date as configured in the settings, so use $format = get_option('date_format');.

To store a user-selected date, you'll have to transcode it into a MySQL date. To do so, the easiest - but not safest - way is date('Y-m-d h:i:s', $unix_timestamp);. $unix_timestamp can often be derived via strtotime($user_input).

However, strtotime() doesn't do sanity checks on it's own, so it's best to write your own converstion function.

As for getting the month range, here's a function i'm using to get the month boundaries for any MySQL timestamp:

function get_monthrange($time) {
    $ym = date("Y-m", strtotime($time));
    $start = $ym."-01";
    $ym = explode("-", $ym);
    if ($ym[1] == 12) {
        $ym[0]++; $ym[1] = 1;
    } else {
        $ym[1]++;
    }
    $d = mktime( 0, 0, 0, $ym[1], 1, $ym[0] );
    $d -= 86400;
    $end = date("Y-m-d", $d);
    return array( $start, $end );
}

If you want to get the week boundaries, WP already comes with a function for that: get_weekstartend($time);, which also delivers the boundaries as an array.

You can then use these in your meta_query argument by doing two separate comparisons.

I wound up going with the following. I setup a event-momth field and comparing from there. thanks for the help

<?php 
        $event_query = new WP_Query(
        array( 
          'post_type'   => 'event',        // only query events
          'meta_key'    => 'event-month',  // load up the event_date meta
          'order_by'        => 'event_date',
          'order'       => 'asc',         // ascending, so earlier events first
          'meta_query'  => array(
             array(         // restrict posts based on meta values
              'key'     => 'event-month',  // which meta to query
              'value'   => date("n"),  // value for comparison
              'compare' => '=',          // method of comparison
              'type'    => 'NUMERIC'         // datatype, we don't want to compare the string values
            ) // meta_query is an array of query ites
           ) // end meta_query array
          ) // end array
        ); // close WP_Query constructor call

 ?>
   <?php while($event_query->have_posts()): $event_query->the_post(); //loop for events ?>