Index: wp-includes/comment.php
===================================================================
--- wp-includes/comment.php	(revision 25018)
+++ wp-includes/comment.php	(working copy)
@@ -197,6 +197,15 @@
 	var $meta_query = false;
 
 	/**
+	 * Date query container
+	 *
+	 * @since 3.7.0
+	 * @access public
+	 * @var object WP_Date_Query
+	 */
+	var $date_query = false;
+
+	/**
 	 * Execute the query
 	 *
 	 * @since 3.1.0
@@ -231,6 +240,7 @@
 			'meta_key' => '',
 			'meta_value' => '',
 			'meta_query' => '',
+			'date_query' => null, // See WP_Date_Query
 		);
 
 		$groupby = '';
@@ -360,6 +370,11 @@
 			$groupby = "{$wpdb->comments}.comment_ID";
 		}
 
+		if ( ! empty( $date_query ) && is_array( $date_query ) ) {
+			$date_query_object = new WP_Date_Query( $date_query, 'comment_date' );
+			$where .= $date_query_object->get_sql();
+		}
+
 		$pieces = array( 'fields', 'join', 'where', 'orderby', 'order', 'limits', 'groupby' );
 		$clauses = apply_filters_ref_array( 'comments_clauses', array( compact( $pieces ), &$this ) );
 		foreach ( $pieces as $piece )
Index: wp-includes/query.php
===================================================================
--- wp-includes/query.php	(revision 25018)
+++ wp-includes/query.php	(working copy)
@@ -867,6 +867,15 @@
 	var $meta_query = false;
 
 	/**
+	 * Date query container
+	 *
+	 * @since 3.7.0
+	 * @access public
+	 * @var object WP_Date_Query
+	 */
+	var $date_query = false;
+
+	/**
 	 * Holds the data for a single object that is queried.
 	 *
 	 * Holds the contents of a post, page, category, attachment.
@@ -1445,7 +1454,7 @@
 		$qv['monthnum'] = absint($qv['monthnum']);
 		$qv['day'] = absint($qv['day']);
 		$qv['w'] = absint($qv['w']);
-		$qv['m'] = absint($qv['m']);
+		$qv['m'] = preg_replace( '|[^0-9]|', '', $qv['m'] );
 		$qv['paged'] = absint($qv['paged']);
 		$qv['cat'] = preg_replace( '|[^0-9,-]|', '', $qv['cat'] ); // comma separated list of positive or negative integers
 		$qv['pagename'] = trim( $qv['pagename'] );
@@ -2045,40 +2054,73 @@
 		if ( '' !== $q['menu_order'] )
 			$where .= " AND $wpdb->posts.menu_order = " . $q['menu_order'];
 
-		// If a month is specified in the querystring, load that month
+		// The "m" parameter is meant for months but accepts datetimes of varying specificity
 		if ( $q['m'] ) {
-			$q['m'] = '' . preg_replace('|[^0-9]|', '', $q['m']);
-			$where .= " AND YEAR($wpdb->posts.post_date)=" . substr($q['m'], 0, 4);
-			if ( strlen($q['m']) > 5 )
-				$where .= " AND MONTH($wpdb->posts.post_date)=" . substr($q['m'], 4, 2);
-			if ( strlen($q['m']) > 7 )
-				$where .= " AND DAYOFMONTH($wpdb->posts.post_date)=" . substr($q['m'], 6, 2);
-			if ( strlen($q['m']) > 9 )
-				$where .= " AND HOUR($wpdb->posts.post_date)=" . substr($q['m'], 8, 2);
-			if ( strlen($q['m']) > 11 )
-				$where .= " AND MINUTE($wpdb->posts.post_date)=" . substr($q['m'], 10, 2);
-			if ( strlen($q['m']) > 13 )
-				$where .= " AND SECOND($wpdb->posts.post_date)=" . substr($q['m'], 12, 2);
+			$m_strlen = strlen( $q['m'] );
+			$m_parameters = array();
+
+			if ( $m_strlen > 3 )
+				$m_parameters['year'] = substr( $q['m'], 0, 4 );
+
+			if ( $m_strlen > 5 )
+				$m_parameters['monthnum'] = substr( $q['m'], 4, 2 );
+
+			if ( $m_strlen > 7 )
+				$m_parameters['day'] = substr( $q['m'], 6, 2 );
+
+			if ( $m_strlen > 9 )
+				$m_parameters['hour'] = substr( $q['m'], 8, 2 );
+
+			if ( $m_strlen > 11 )
+				$m_parameters['minute'] = substr( $q['m'], 10, 2 );
+
+			if ( $m_strlen > 13 )
+				$m_parameters['second'] = substr( $q['m'], 12, 2 );
+
+			if ( $m_parameters ) {
+				$date_query = new WP_Date_Query( array( $m_parameters ) );
+				$where .= $date_query->get_sql();
+			}
+			unset( $m_parameters, $date_query );
 		}
 
+		// Handle the other individual date parameters
+		$date_parameters = array();
+
 		if ( '' !== $q['hour'] )
-			$where .= " AND HOUR($wpdb->posts.post_date)='" . $q['hour'] . "'";
+			$date_parameters['hour'] = $q['hour'];
 
 		if ( '' !== $q['minute'] )
-			$where .= " AND MINUTE($wpdb->posts.post_date)='" . $q['minute'] . "'";
+			$date_parameters['minute'] = $q['minute'];
 
 		if ( '' !== $q['second'] )
-			$where .= " AND SECOND($wpdb->posts.post_date)='" . $q['second'] . "'";
+			$date_parameters['second'] = $q['second'];
 
 		if ( $q['year'] )
-			$where .= " AND YEAR($wpdb->posts.post_date)='" . $q['year'] . "'";
+			$date_parameters['year'] = $q['year'];
 
 		if ( $q['monthnum'] )
-			$where .= " AND MONTH($wpdb->posts.post_date)='" . $q['monthnum'] . "'";
+			$date_parameters['monthnum'] = $q['monthnum'];
 
+		if ( $q['w'] )
+			$date_parameters['week'] = $q['w'];
+
 		if ( $q['day'] )
-			$where .= " AND DAYOFMONTH($wpdb->posts.post_date)='" . $q['day'] . "'";
+			$date_parameters['day'] = $q['day'];
 
+		if ( $date_parameters ) {
+			$date_query = new WP_Date_Query( array( $date_parameters ) );
+			$where .= $date_query->get_sql();
+		}
+		unset( $date_parameters, $date_query );
+
+		// Handle complex date queries
+		if ( ! empty( $q['date_query'] ) ) {
+			$this->date_query = new WP_Date_Query( $q['date_query'] );
+			$where .= $this->date_query->get_sql();
+		}
+
+
 		// If we've got a post_type AND it's not "any" post_type.
 		if ( !empty($q['post_type']) && 'any' != $q['post_type'] ) {
 			foreach ( (array)$q['post_type'] as $_post_type ) {
@@ -2147,8 +2189,6 @@
 			$where .= " AND $wpdb->posts.post_name = '" . $q['attachment'] . "'";
 		}
 
-		if ( $q['w'] )
-			$where .= ' AND ' . _wp_mysql_week( "`$wpdb->posts`.`post_date`" ) . " = '" . $q['w'] . "'";
 
 		if ( intval($q['comments_popup']) )
 			$q['p'] = absint($q['comments_popup']);
@@ -3571,6 +3611,401 @@
 }
 
 /**
+ * WP_Date_Query will generate a MySQL WHERE clause for the specified date-based parameters.
+ *
+ * Initialize the class by passing an array of arrays of parameters. Example:
+ *
+ * $date_query = new WP_Date_Query( array(
+ * 		'column' => 'optional, column to query against, default is post_date',
+ * 		'compare' => 'optional, see WP_Date_Query::get_compare()',
+ * 		'relation' => 'optional, OR or AND, how the sub-arrays should be compared, default is AND',
+ * 		array(
+ * 			'column' => 'see above',
+ * 			'compare' => 'see above',
+ * 			'after' => 'string or array, see WP_Date_Query::build_mysql_datetime()',
+ * 			'before' => 'string or array, see WP_Date_Query::build_mysql_datetime()',
+ * 			'inclusive' => 'boolean, for after/before, whether exact value should be matched or not',
+ * 			'year' => '4 digit int',
+ * 			'month' => 'int, 1-12',
+ * 			'week' => 'int, 0-53',
+ * 			'day' => 'int, 1-31',
+ * 			'hour' => 'int, 0-23',
+ * 			'minute' => 'int, 0-60',
+ * 			'second' => 'int, 0-60',
+ * 		),
+ *		array(
+ *			...
+ *		),
+ *		...
+ * ) );
+ *
+ * Then call the get_sql() method to get the MySQL WHERE string:
+ *
+ * $where .= $date_query->get_sql();
+ *
+ * @link http://codex.wordpress.org/Function_Reference/WP_Query Codex page.
+ *
+ * @since 3.7.0
+ */
+class WP_Date_Query {
+	/**
+	 * List of date queries.
+	 *
+	 * @since 3.7.0
+	 * @access public
+	 * @var array
+	 */
+	public $queries = array();
+
+	/**
+	 * The relation between the queries. Can be either 'AND' or 'OR' and can be changed via the query arguments.
+	 *
+	 * @since 3.7.0
+	 * @access public
+	 * @var string
+	 */
+	public $relation = 'AND';
+
+	/**
+	 * The column to query against. Can be changed via the query arguments.
+	 *
+	 * @since 3.7.0
+	 * @access public
+	 * @var string
+	 */
+	public $column = 'post_date';
+
+	/**
+	 * The value comparison operator. Can be changed via the query arguments.
+	 *
+	 * @since 3.7.0
+	 * @access public
+	 * @var array
+	 */
+	public $compare = '=';
+
+	/**
+	 * Constructor
+	 *
+	 * @param array $date_query A date query parameter array, see class descriptor for further details.
+	 * @param array (optional) $default_column What column name to query against. Defaults to "post_date".
+	 */
+	function __construct( $date_query, $default_column = 'post_date' ) {
+		if ( empty( $date_query ) || ! is_array( $date_query ) )
+			return;
+
+		if ( isset( $date_query['relation'] ) && strtoupper( $date_query['relation'] ) == 'OR' ) {
+			$this->relation = 'OR';
+		} else {
+			$this->relation = 'AND';
+		}
+
+		if ( ! empty( $date_query['column'] ) )
+			$this->column = esc_sql( $date_query['column'] );
+		else
+			$this->column = esc_sql( $default_column );
+
+		$this->column = $this->validate_column( $this->column );
+
+		$this->compare = $this->get_compare( $date_query );
+
+		// If an array of arrays wasn't passed, fix it
+		if ( ! isset( $date_query[0] ) )
+			$date_query = array( $date_query );
+
+		$this->queries = array();
+		foreach ( $date_query as $key => $query ) {
+			if ( ! is_array( $query ) )
+				continue;
+
+			$this->queries[$key] = $query;
+		}
+	}
+
+	/**
+	 * Determines and validates what comparison operator to use.
+	 *
+	 * @since 3.7.0
+	 * @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;
+	}
+
+	/**
+	 * Validates a column name parameter.
+	 *
+	 * @since 3.7.0
+	 * @access public
+	 *
+	 * @param string $column The user-supplied column name.
+	 * @return string A validated column name value.
+	 */
+	public function validate_column( $column ) {
+		if ( ! in_array( $column, apply_filters( 'date_query_valid_columns', array( 'post_date', 'post_date_gmt', 'post_modified', 'post_modified_gmt', 'comment_date', 'comment_date_gmt' ) ) ) )
+			$column = 'post_date';
+
+		return $column;
+	}
+
+	/**
+	 * Turns an array of date query parameters into a MySQL string.
+	 *
+	 * @since 3.7.0
+	 * @access public
+	 *
+	 * @return string MySQL WHERE parameters
+	 */
+	public function get_sql() {
+		global $wpdb;
+
+		// The parts of the final query
+		$where = array();
+
+		foreach ( $this->queries as $key => $query ) {
+
+			// The sub-parts of a $where part
+			$where_parts = array();
+
+			$column = ( ! empty( $query['column'] ) ) ? esc_sql( $query['column'] ) : $this->column;
+
+			$column = $this->validate_column( $column );
+
+			$compare = $this->get_compare( $query );
+
+			$lt = '<';
+			$gt = '>';
+			if ( ! empty( $query['inclusive'] ) ) {
+				$lt .= '=';
+				$gt .= '=';
+			}
+
+			// Range queries
+			if ( ! empty( $query['after'] ) )
+				$where_parts[] = $wpdb->prepare( "$column $gt %s", $this->build_mysql_datetime( $query['after'], true ) );
+
+			if ( ! empty( $query['before'] ) )
+				$where_parts[] = $wpdb->prepare( "$column $lt %s", $this->build_mysql_datetime( $query['before'], false ) );
+
+			// Specific value queries
+
+			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'] ) && false !== ( $value = $this->build_value( $compare, $query['week'] ) ) )
+				$where_parts[] = _wp_mysql_week( $column ) . " $compare $value";
+
+			// Legacy
+			if ( isset( $query['w'] ) && false !== ( $value = $this->build_value( $compare, $query['w'] ) ) )
+				$where_parts[] = _wp_mysql_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'] ) ) {
+				// Avoid notices
+				foreach ( array( 'hour', 'minute', 'second' ) as $unit ) {
+					if ( ! isset( $query[$unit] ) ) {
+						$query[$unit] = null;
+					}
+				}
+
+				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 );
+	}
+
+	/**
+	 * Builds and validates a value string based on the comparison operator.
+	 *
+	 * @since 3.7.0
+	 * @access public
+	 *
+	 * @param string $compare The compare operator to use
+	 * @param string|array $value The value
+	 * @return string|int|false The value to be used in SQL or false on error.
+	 */
+	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
+	 * either the maximum or minimum values (controlled by the $default_to parameter). Alternatively you can
+	 * pass a string that that will be run through strtotime().
+	 *
+	 * @since 3.7.0
+	 * @access public
+	 *
+	 * @param string|array $datetime An array of parameters or a strotime() string
+	 * @param string $default_to Controls what values default to if they are missing from $datetime. Pass "min" or "max".
+	 * @return string|false A MySQL format date/time or false on failure
+	 */
+	public function build_mysql_datetime( $datetime, $default_to_max = false ) {
+		$now = current_time( 'timestamp' );
+
+		if ( is_array( $datetime ) ) {
+			$datetime = array_map( 'absint', $datetime );
+
+			if ( ! isset( $datetime['year'] ) )
+				$datetime['year'] = gmdate( 'Y', $now );
+
+			if ( ! isset( $datetime['month'] ) )
+				$datetime['month'] = ( $default_to_max ) ? 12 : 1;
+
+			if ( ! isset( $datetime['day'] ) )
+				$datetime['day'] = ( $default_to_max ) ? (int) date( 't', mktime( 0, 0, 0, $datetime['month'], 1, $datetime['year'] ) ) : 1;
+
+			if ( ! isset( $datetime['hour'] ) )
+				$datetime['hour'] = ( $default_to_max ) ? 23 : 0;
+
+			if ( ! isset( $datetime['minute'] ) )
+				$datetime['minute'] = ( $default_to_max ) ? 59 : 0;
+
+			if ( ! isset( $datetime['second'] ) )
+				$datetime['second'] = ( $default_to_max ) ? 59 : 0;
+
+			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 3.7.0
+	 * @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 ) && false !== ( $value = $this->build_value( $compare, $hour ) ) )
+				$return[] = "HOUR( $column ) $compare $value";
+
+			if ( isset( $minute ) && false !== ( $value = $this->build_value( $compare, $minute ) ) )
+				$return[] = "MINUTE( $column ) $compare $value";
+
+			if ( isset( $second ) && false !== ( $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 ) && false !== ( $value = $this->build_value( $compare, $hour ) ) ) {
+			return "HOUR( $column ) $compare $value";
+		} elseif ( ! isset( $hour ) && isset( $minute ) && ! isset( $second ) && false !== ( $value = $this->build_value( $compare, $minute ) ) ) {
+			return "MINUTE( $column ) $compare $value";
+		} elseif ( ! isset( $hour ) && ! isset( $minute ) && isset( $second ) && false !== ( $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 );
+	}
+}
+
+/**
  * Redirect old slugs to the correct permalink.
  *
  * Attempts to find the current slug from the past slugs.