Index: wp-includes/query.php
===================================================================
--- wp-includes/query.php	(revision 18776)
+++ wp-includes/query.php	(working copy)
@@ -2075,6 +2075,12 @@
 		if ( $q['day'] )
 			$where .= " AND DAYOFMONTH($wpdb->posts.post_date)='" . $q['day'] . "'";
 
+		// Temporary
+		if ( ! empty( $q['date_query'] ) ) {
+			$date_query = new WP_Date_Query( $q['date_query'] );
+			$where .= $date_query->get_sql();
+		}
+
 		// If we've got a post_type AND its not "any" post_type.
 		if ( !empty($q['post_type']) && 'any' != $q['post_type'] ) {
 			foreach ( (array)$q['post_type'] as $_post_type ) {
@@ -3554,6 +3560,367 @@
 }
 
 /**
+ * Container class for a date query
+ *
+ * @since 3.4.0
+ */
+class WP_Date_Query {
+	/**
+	* List of date queries. A single query is an associative array:
+	*
+	* TODO: DOCUMENT AVAILABLE VARS
+	*
+	* @since 3.4.0
+	* @access public
+	* @var array
+	*/
+	public $queries = array();
+
+	/**
+	 * The relation between the queries. Can be one of 'AND' or 'OR'.
+	 *
+	 * @since 3.4.0
+	 * @access public
+	 * @var string
+	 */
+	public $relation;
+
+	/**
+	 * The column to query against. Can be changed via the query arguments.
+	 *
+	 * @since 3.4.0
+	 * @access public
+	 * @var string
+	 */
+	public $column = 'post_date';
+
+	/**
+	 * The value comparison operator. Can be changed via the query arguments.
+	 *
+	 * @since 3.4.0
+	 * @access public
+	 * @var array
+	 */
+	public $compare = '=';
+
+	/**
+	 * Constructor
+	 *
+	 * @param array (optional) $date_query A date query parameter array
+	 */
+	function __construct( $date_query = false ) {
+		if ( empty( $date_query ) || ! is_array( $date_query ) )
+			return false;
+
+		if ( isset( $date_query['relation'] ) && strtoupper( $date_query['relation'] ) == 'OR' ) {
+			$this->relation = 'OR';
+		} else {
+			$this->relation = 'AND';
+		}
+
+		$this->column  = $this->get_column( $date_query );
+		$this->compare = $this->get_compare( $date_query );
+
+		$this->queries = array();
+		foreach ( $date_query as $key => $query ) {
+			if ( ! is_array( $query ) )
+				continue;
+
+			$this->queries[$key] = $query;
+		}
+	}
+
+	/**
+	 * Determines and validates what database column to query against.
+	 *
+	 * @since 3.4.0
+	 * @access public
+	 *
+	 * @param array $query A date query or a date subquery
+	 * @return string The column to query against
+	 */
+	public function get_column( $query ) {
+		if ( isset( $query['column'] ) && in_array( $query['column'], array( 'post_date', 'post_date_gmt', 'post_modified', 'post_modified_gmt' ) ) )
+			return strtolower( $query['column'] );
+
+		return $this->column;
+	}
+
+	/**
+	 * Determines and validates what comparison operator to use.
+	 *
+	 * @since 3.4.0
+	 * @access public
+	 *
+	 * @param array $query A date query or a date subquery
+	 * @return string The comparison operator
+	 */
+	public function get_compare( $query ) {
+		if ( ! empty( $query['compare'] ) && in_array( $query['compare'], array( '=', '!=', '>', '>=', '<', '<=', 'IN', 'NOT IN', 'BETWEEN', 'NOT BETWEEN' ) ) )
+			return strtoupper( $query['compare'] );
+
+		return $this->compare;
+	}
+
+	/**
+	 * Turns an array of date query parameters into a MySQL string.
+	 *
+	 * @since 3.4.0
+	 * @access public
+	 *
+	 * @return string MySQL WHERE parameters
+	 */
+	public function get_sql() {
+		global $wpdb;
+
+		// The parts of the final query
+		$where = array();
+
+		$valid_args = array(
+			'column',
+			'compare',
+			'inclusive',
+			'after',
+			'before',
+			'hour',
+			'minute',
+			'second',
+			'dayofweek',
+		);
+
+		foreach ( $this->queries as $key => $query ) {
+			// Makes life easier while avoiding notices
+			foreach ( $valid_args as $valid_arg ) {
+				if ( ! isset( $query[$valid_arg] ) ) {
+					$query[$valid_arg] = null;
+				}
+			}
+
+			// The parts of a $where part (Queryception!)
+			$where_parts = array();
+
+			// Figure out what column to use in this subquery, defaulting to the overall column
+			$column = $wpdb->posts . '.' . $this->get_column( $query );
+
+			// Range queries
+			if ( ! empty( $query['after'] ) || ! empty( $query['before'] ) ) {
+				$lt = ( $query['inclusive'] ) ? '<=' : '<';
+				$gt = ( $query['inclusive'] ) ? '>=' : '>';
+
+				if ( $query['after'] )
+					$where_parts[] = $wpdb->prepare( "$column $gt %s", $this->build_mysql_datetime( $query['after'] ) );
+				
+				if ( $query['before'] )
+					$where_parts[] = $wpdb->prepare( "$column $lt %s", $this->build_mysql_datetime( $query['before'] ) );
+			}
+
+			// Specific value queries
+			else {
+				$compare = $this->get_compare( $query );
+
+				if ( isset( $query['year'] ) && $value = $this->build_value( $compare, $query['year'] ) )
+					$where_parts[] = "YEAR( $column ) $compare $value";
+
+				if ( isset( $query['month'] ) && $value = $this->build_value( $compare, $query['month'] ) )
+					$where_parts[] = "MONTH( $column ) $compare $value";
+
+				// Legacy
+				if ( isset( $query['monthnum'] ) && $value = $this->build_value( $compare, $query['monthnum'] ) )
+					$where_parts[] = "MONTH( $column ) $compare $value";
+
+				if ( isset( $query['week'] ) && $value = $this->build_value( $compare, $query['week'] ) )
+					$where_parts[] = "WEEK( $column ) $compare $value";
+
+				// Legacy
+				if ( isset( $query['w'] ) && $value = $this->build_value( $compare, $query['w'] ) )
+					$where_parts[] = "WEEK( $column ) $compare $value";
+
+				if ( isset( $query['dayofyear'] ) && $value = $this->build_value( $compare, $query['dayofyear'] ) )
+					$where_parts[] = "DAYOFYEAR( $column ) $compare $value";
+
+				if ( isset( $query['day'] ) && $value = $this->build_value( $compare, $query['day'] ) )
+					$where_parts[] = "DAYOFMONTH( $column ) $compare $value";
+
+				if ( isset( $query['dayofweek'] ) && $value = $this->build_value( $compare, $query['dayofweek'] ) )
+					$where_parts[] = "DAYOFWEEK( $column ) $compare $value";
+
+				if ( isset( $query['hour'] ) || isset( $query['minute'] ) || isset( $query['second'] ) ) {
+					if ( $time_query = $this->build_time_query( $column, $compare, $query['hour'], $query['minute'], $query['second'] ) ) {
+						$where_parts[] = $time_query;
+					}
+				}
+			}
+
+			// Combine the parts of this subquery into a single string
+			if ( ! empty( $where_parts ) )
+				$where[$key] = '( ' . implode( ' AND ', $where_parts ) . ' )';
+		}
+
+		// Combine the subquery strings into a single string
+		if ( ! empty( $where ) )
+			$where = ' AND ( ' . implode( " {$this->relation} ", $where ) . ' )';
+		else
+			$where = '';
+
+		return apply_filters( 'get_date_sql', $where, $this->queries );
+	}
+
+	/**
+	 * Builds and validates a value string based on the comparison operator.
+	 *
+	 * @since 3.4.0
+	 * @access public
+	 *
+	 * @param string $compare The compare operator to use
+	 * @param string|array $value The value
+	 * @return string|int The value to be used in SQL
+	 */
+	public function build_value( $compare, $value ) {
+		if ( ! isset( $value ) )
+			return false;
+
+		switch ( $compare ) {
+			case 'IN':
+			case 'NOT IN':
+				return '(' . implode( ',', array_map( 'intval', (array) $value ) ) . ')';
+
+			case 'BETWEEN':
+			case 'NOT BETWEEN':
+				if ( ! is_array( $value ) || 2 != count( $value ) || ! isset( $value[0] ) || ! isset( $value[1] ) )
+					$value = array( $value, $value );
+
+				$value = array_map( 'intval', $value );
+
+				return $value[0] . ' AND ' . $value[1];
+
+			default;
+				return (int) $value;
+		}
+	}
+
+	/**
+	 * Builds a MySQL format date/time based on some query parameters.
+	 *
+	 * You can pass an array of values (year, month, etc.) with missing parameter values being defaulted to 0
+	 * or you can pass a string that will be run through strtotime().
+	 *
+	 * @since 3.4.0
+	 * @access public
+	 *
+	 * @param string|array $datetime An array of parameters or a strotime() string
+	 * @return string|false A MySQL format date/time or false on failure
+	 */
+	public function build_mysql_datetime( $datetime ) {
+		$now = current_time( 'timestamp' );
+
+		if ( is_array( $datetime ) ) {
+			if ( ! isset( $datetime['year'] ) )
+				$datetime['year'] = gmdate( 'Y', $now );
+
+			if ( ! isset( $datetime['month'] ) )
+				$datetime['month'] = 1;
+
+			if ( ! isset( $datetime['day'] ) )
+				$datetime['day'] = 1;
+
+			if ( ! isset( $datetime['hour'] ) )
+				$datetime['hour'] = 0;
+
+			if ( ! isset( $datetime['minute'] ) )
+				$datetime['minute'] = 0;
+
+			if ( ! isset( $datetime['second'] ) )
+				$datetime['second'] = 0;
+
+			$datetime = array_map( 'intval', $datetime );
+
+			return sprintf( '%04d-%02d-%02d %02d:%02d:%02d', $datetime['year'], $datetime['month'], $datetime['day'], $datetime['hour'], $datetime['minute'], $datetime['second'] );
+		} else {
+			// Timezone issues here possibly
+			return gmdate( 'Y-m-d H:i:s', strtotime( $datetime, $now ) );
+		}
+
+		return false;
+	}
+
+	/**
+	 * Builds a query string for comparing time values (hour, minute, second).
+	 *
+	 * If just hour, minute, or second is set than a normal comparison will be done.
+	 * However if multiple values are passed, a pseudo-decimal time will be created
+	 * in order to be able to accurately compare against.
+	 *
+	 * @since 3.4.0
+	 * @access public
+	 *
+	 * @param string $column The column to query against. Needs to be pre-validated!
+	 * @param string $compare The comparison operator. Needs to be pre-validated!
+	 * @param int|null $hour Optional. An hour value (0-23).
+	 * @param int|null $minute Optional. A minute value (0-59).
+	 * @param int|null $second Optional. A second value (0-59).
+	 * @return string|false A query part or false on failure.
+	 */
+	public function build_time_query( $column, $compare, $hour = null, $minute = null, $second = null ) {
+		global $wpdb;
+
+		// Have to have at least one
+		if ( ! isset( $hour ) && ! isset( $minute ) && ! isset( $second ) )
+			return false;
+
+		// Complex combined queries aren't supported for multi-value queries
+		if ( in_array( $compare, array( 'IN', 'NOT IN', 'BETWEEN', 'NOT BETWEEN' ) ) ) {
+			$return = array();
+
+			if ( isset( $hour ) && $value = $this->build_value( $compare, $hour ) )
+				$return[] = "HOUR( $column ) $compare $value";
+
+			if ( isset( $minute ) && $value = $this->build_value( $compare, $minute ) )
+				$return[] = "MINUTE( $column ) $compare $value";
+
+			if ( isset( $second ) && $value = $this->build_value( $compare, $second ) )
+				$return[] = "SECOND( $column ) $compare $value";
+
+			return implode( ' AND ', $return );
+		}
+
+		// Cases where just one unit is set
+		if ( isset( $hour ) && ! isset( $minute ) && ! isset( $second ) && $value = $this->build_value( $compare, $hour ) ) {
+			return "HOUR( $column ) $compare $value";
+		} elseif ( ! isset( $hour ) && isset( $minute ) && ! isset( $second ) && $value = $this->build_value( $compare, $minute ) ) {
+			return "MINUTE( $column ) $compare $value";
+		} elseif ( ! isset( $hour ) && ! isset( $minute ) && isset( $second ) && $value = $this->build_value( $compare, $second ) ) {
+			return "SECOND( $column ) $compare $value";
+		}
+
+		// Single units were already handled. Since hour & second isn't allowed, minute must to be set.
+		if ( ! isset( $minute ) )
+			return false;
+
+		$format = $time = '';
+
+		// Hour
+		if ( $hour ) {
+			$format .= '%H.';
+			$time   .= sprintf( '%02d', $hour ) . '.';
+		} else {
+			$format .= '0.';
+			$time   .= '0.';
+		}
+
+		// Minute
+		$format .= '%i';
+		$time   .= sprintf( '%02d', $minute );
+
+		if ( isset( $second ) ) {
+			$format .= '%s';
+			$time   .= sprintf( '%02d', $second );
+		}
+
+		return $wpdb->prepare( "DATE_FORMAT( $column, %s ) $compare %f", $format, $time );
+	}
+}
+
+/**
  * Set up global post data.
  *
  * @since 1.5.0
@@ -3596,4 +3963,5 @@
 
 	return true;
 }
-?>
+
+?>
\ No newline at end of file