Index: wp-includes/bookmark.php
===================================================================
--- wp-includes/bookmark.php	(revision 6217)
+++ wp-includes/bookmark.php	(working copy)
@@ -112,7 +112,7 @@
 	}
 	if (!empty($category_query)) {
 		$category_query .= ") AND taxonomy = 'link_category'";
-		$join = " LEFT JOIN $wpdb->term_relationships AS tr ON ($wpdb->links.link_id = tr.object_id) LEFT JOIN $wpdb->term_taxonomy as tt ON tt.term_taxonomy_id = tr.term_taxonomy_id";
+		$join = " INNER JOIN $wpdb->term_relationships AS tr ON ($wpdb->links.link_id = tr.object_id) INNER JOIN $wpdb->term_taxonomy as tt ON tt.term_taxonomy_id = tr.term_taxonomy_id";
 	}
 
 	if (get_option('links_recently_updated_time')) {
Index: wp-includes/query.php
===================================================================
--- wp-includes/query.php	(revision 6217)
+++ wp-includes/query.php	(working copy)
@@ -932,7 +932,7 @@
 		}
 
 		if ( !empty($q['category__in']) ) {
-			$join = " LEFT JOIN $wpdb->term_relationships ON ($wpdb->posts.ID = $wpdb->term_relationships.object_id) LEFT JOIN $wpdb->term_taxonomy ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id) ";
+			$join = " INNER JOIN $wpdb->term_relationships ON ($wpdb->posts.ID = $wpdb->term_relationships.object_id) INNER JOIN $wpdb->term_taxonomy ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id) ";
 			$whichcat .= " AND $wpdb->term_taxonomy.taxonomy = 'category' ";
 			$include_cats = "'" . implode("', '", $q['category__in']) . "'";
 			$whichcat .= " AND $wpdb->term_taxonomy.term_id IN ($include_cats) ";
@@ -973,7 +973,7 @@
 
 			$q['cat'] = $reqcat;
 
-			$join = " LEFT JOIN $wpdb->term_relationships ON ($wpdb->posts.ID = $wpdb->term_relationships.object_id) LEFT JOIN $wpdb->term_taxonomy ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id) ";
+			$join = " INNER JOIN $wpdb->term_relationships ON ($wpdb->posts.ID = $wpdb->term_relationships.object_id) INNER JOIN $wpdb->term_taxonomy ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id) ";
 			$whichcat = " AND $wpdb->term_taxonomy.taxonomy = 'category' ";
 			$in_cats = array($q['cat']);
 			$in_cats = array_merge($in_cats, get_term_children($q['cat'], 'category'));
@@ -1015,7 +1015,7 @@
 		}
 
 		if ( !empty($q['tag__in']) ) {
-			$join = " LEFT JOIN $wpdb->term_relationships ON ($wpdb->posts.ID = $wpdb->term_relationships.object_id) LEFT JOIN $wpdb->term_taxonomy ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id) ";
+			$join = " INNER JOIN $wpdb->term_relationships ON ($wpdb->posts.ID = $wpdb->term_relationships.object_id) INNER JOIN $wpdb->term_taxonomy ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id) ";
 			$whichcat .= " AND $wpdb->term_taxonomy.taxonomy = 'post_tag' ";
 			$include_tags = "'" . implode("', '", $q['tag__in']) . "'";
 			$whichcat .= " AND $wpdb->term_taxonomy.term_id IN ($include_tags) ";
@@ -1025,7 +1025,7 @@
 		}
 
 		if ( !empty($q['tag_slug__in']) ) {
-			$join = " LEFT JOIN $wpdb->term_relationships ON ($wpdb->posts.ID = $wpdb->term_relationships.object_id) LEFT JOIN $wpdb->term_taxonomy ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id) LEFT JOIN $wpdb->terms ON ($wpdb->term_taxonomy.term_id = $wpdb->terms.term_id) ";
+			$join = " INNER JOIN $wpdb->term_relationships ON ($wpdb->posts.ID = $wpdb->term_relationships.object_id) INNER JOIN $wpdb->term_taxonomy ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id) INNER JOIN $wpdb->terms ON ($wpdb->term_taxonomy.term_id = $wpdb->terms.term_id) ";
 			$whichcat .= " AND $wpdb->term_taxonomy.taxonomy = 'post_tag' ";
 			$include_tags = "'" . implode("', '", $q['tag_slug__in']) . "'";
 			$whichcat .= " AND $wpdb->terms.slug IN ($include_tags) ";
@@ -1056,7 +1056,7 @@
 			$taxonomy_field = $item == 'tag_slug__and' ? 'slug' : 'term_id';
 
 			$q[$item] = array_unique($q[$item]);
-			$tsql = "SELECT p.ID FROM $wpdb->posts p LEFT JOIN $wpdb->term_relationships tr ON (p.ID = tr.object_id) LEFT JOIN $wpdb->term_taxonomy tt ON (tr.term_taxonomy_id = tt.term_taxonomy_id) LEFT JOIN $wpdb->terms t ON (tt.term_id = t.term_id)";
+			$tsql = "SELECT p.ID FROM $wpdb->posts p INNER JOIN $wpdb->term_relationships tr ON (p.ID = tr.object_id) INNER JOIN $wpdb->term_taxonomy tt ON (tr.term_taxonomy_id = tt.term_taxonomy_id) INNER JOIN $wpdb->terms t ON (tt.term_id = t.term_id)";
 			$tsql .= " WHERE tt.taxonomy = '$taxonomy' AND t.$taxonomy_field IN ('" . implode("', '", $q[$item]) . "')";
 			$tsql .= " GROUP BY p.ID HAVING count(p.ID) = " . count($q[$item]);
 
Index: wp-includes/taxonomy.php
===================================================================
--- wp-includes/taxonomy.php	(revision 6217)
+++ wp-includes/taxonomy.php	(working copy)
@@ -1357,7 +1357,7 @@
 	}
 
 	// Get the object and term ids and stick them in a lookup table
-	$results = $wpdb->get_results("SELECT object_id, term_taxonomy_id FROM $wpdb->term_relationships LEFT JOIN $wpdb->posts ON object_id = ID WHERE term_taxonomy_id IN (".join(',', array_keys($term_ids)).") AND post_type = 'post' AND post_status = 'publish'");
+	$results = $wpdb->get_results("SELECT object_id, term_taxonomy_id FROM $wpdb->term_relationships INNER JOIN $wpdb->posts ON object_id = ID WHERE term_taxonomy_id IN (".join(',', array_keys($term_ids)).") AND post_type = 'post' AND post_status = 'publish'");
 	foreach ( $results as $row ) {
 		$id = $term_ids[$row->term_taxonomy_id];
 		++$term_items[$id][$row->object_id];