diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index f95cb6149fc43..f088bda6da6d0 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -474,6 +474,16 @@ class WP_Query {
 
 	private $compat_methods = array( 'init_query_flags', 'parse_tax_query' );
 
+	/**
+	 * The cache key generated by the query.
+	 *
+	 * The cache key is generated by the method ::generate_cache_key() after the
+	 * query has been normalized.
+	 *
+	 * @var string
+	 */
+	private $query_cache_key = '';
+
 	/**
 	 * Resets query flags to false.
 	 *
@@ -1101,7 +1111,8 @@ public function parse_query( $query = '' ) {
 
 		if ( ! empty( $qv['post_type'] ) ) {
 			if ( is_array( $qv['post_type'] ) ) {
-				$qv['post_type'] = array_map( 'sanitize_key', $qv['post_type'] );
+				$qv['post_type'] = array_map( 'sanitize_key', array_unique( $qv['post_type'] ) );
+				sort( $qv['post_type'] );
 			} else {
 				$qv['post_type'] = sanitize_key( $qv['post_type'] );
 			}
@@ -1109,7 +1120,8 @@ public function parse_query( $query = '' ) {
 
 		if ( ! empty( $qv['post_status'] ) ) {
 			if ( is_array( $qv['post_status'] ) ) {
-				$qv['post_status'] = array_map( 'sanitize_key', $qv['post_status'] );
+				$qv['post_status'] = array_map( 'sanitize_key', array_unique( $qv['post_status'] ) );
+				sort( $qv['post_status'] );
 			} else {
 				$qv['post_status'] = preg_replace( '|[^a-z0-9_,-]|', '', $qv['post_status'] );
 			}
@@ -1182,9 +1194,12 @@ public function parse_tax_query( &$q ) {
 
 				$term = $q[ $t->query_var ];
 
-				if ( is_array( $term ) ) {
-					$term = implode( ',', $term );
+				if ( ! is_array( $term ) ) {
+					$term = explode( ',', $term );
+					$term = array_map( 'trim', $term );
 				}
+				sort( $term );
+				$term = implode( ',', $term );
 
 				if ( str_contains( $term, '+' ) ) {
 					$terms = preg_split( '/[+]+/', $term );
@@ -1220,7 +1235,8 @@ public function parse_tax_query( &$q ) {
 
 			$cat_array = preg_split( '/[,\s]+/', urldecode( $q['cat'] ) );
 			$cat_array = array_map( 'intval', $cat_array );
-			$q['cat']  = implode( ',', $cat_array );
+			sort( $cat_array );
+			$q['cat'] = implode( ',', $cat_array );
 
 			foreach ( $cat_array as $cat ) {
 				if ( $cat > 0 ) {
@@ -1262,7 +1278,8 @@ public function parse_tax_query( &$q ) {
 
 		if ( ! empty( $q['category__in'] ) ) {
 			$q['category__in'] = array_map( 'absint', array_unique( (array) $q['category__in'] ) );
-			$tax_query[]       = array(
+			sort( $q['category__in'] );
+			$tax_query[] = array(
 				'taxonomy'         => 'category',
 				'terms'            => $q['category__in'],
 				'field'            => 'term_id',
@@ -1272,6 +1289,7 @@ public function parse_tax_query( &$q ) {
 
 		if ( ! empty( $q['category__not_in'] ) ) {
 			$q['category__not_in'] = array_map( 'absint', array_unique( (array) $q['category__not_in'] ) );
+			sort( $q['category__not_in'] );
 			$tax_query[]           = array(
 				'taxonomy'         => 'category',
 				'terms'            => $q['category__not_in'],
@@ -1282,7 +1300,8 @@ public function parse_tax_query( &$q ) {
 
 		if ( ! empty( $q['category__and'] ) ) {
 			$q['category__and'] = array_map( 'absint', array_unique( (array) $q['category__and'] ) );
-			$tax_query[]        = array(
+			sort( $q['category__and'] );
+			$tax_query[] = array(
 				'taxonomy'         => 'category',
 				'terms'            => $q['category__and'],
 				'field'            => 'term_id',
@@ -1300,10 +1319,12 @@ public function parse_tax_query( &$q ) {
 
 		if ( '' !== $q['tag'] && ! $this->is_singular && $this->query_vars_changed ) {
 			if ( str_contains( $q['tag'], ',' ) ) {
+				// @todo Handle normalizing `tag` query string.
 				$tags = preg_split( '/[,\r\n\t ]+/', $q['tag'] );
 				foreach ( (array) $tags as $tag ) {
 					$tag                 = sanitize_term_field( 'slug', $tag, 0, 'post_tag', 'db' );
 					$q['tag_slug__in'][] = $tag;
+					sort( $q['tag_slug__in'] );
 				}
 			} elseif ( preg_match( '/[+\r\n\t ]+/', $q['tag'] ) || ! empty( $q['cat'] ) ) {
 				$tags = preg_split( '/[+\r\n\t ]+/', $q['tag'] );
@@ -1314,6 +1335,7 @@ public function parse_tax_query( &$q ) {
 			} else {
 				$q['tag']            = sanitize_term_field( 'slug', $q['tag'], 0, 'post_tag', 'db' );
 				$q['tag_slug__in'][] = $q['tag'];
+				sort( $q['tag_slug__in'] );
 			}
 		}
 
@@ -1327,7 +1349,8 @@ public function parse_tax_query( &$q ) {
 
 		if ( ! empty( $q['tag__in'] ) ) {
 			$q['tag__in'] = array_map( 'absint', array_unique( (array) $q['tag__in'] ) );
-			$tax_query[]  = array(
+			sort( $q['tag__in'] );
+			$tax_query[] = array(
 				'taxonomy' => 'post_tag',
 				'terms'    => $q['tag__in'],
 			);
@@ -1335,6 +1358,7 @@ public function parse_tax_query( &$q ) {
 
 		if ( ! empty( $q['tag__not_in'] ) ) {
 			$q['tag__not_in'] = array_map( 'absint', array_unique( (array) $q['tag__not_in'] ) );
+			sort( $q['tag__not_in'] );
 			$tax_query[]      = array(
 				'taxonomy' => 'post_tag',
 				'terms'    => $q['tag__not_in'],
@@ -1344,7 +1368,8 @@ public function parse_tax_query( &$q ) {
 
 		if ( ! empty( $q['tag__and'] ) ) {
 			$q['tag__and'] = array_map( 'absint', array_unique( (array) $q['tag__and'] ) );
-			$tax_query[]   = array(
+			sort( $q['tag__and'] );
+			$tax_query[] = array(
 				'taxonomy' => 'post_tag',
 				'terms'    => $q['tag__and'],
 				'operator' => 'AND',
@@ -1353,7 +1378,8 @@ public function parse_tax_query( &$q ) {
 
 		if ( ! empty( $q['tag_slug__in'] ) ) {
 			$q['tag_slug__in'] = array_map( 'sanitize_title_for_query', array_unique( (array) $q['tag_slug__in'] ) );
-			$tax_query[]       = array(
+			sort( $q['tag_slug__in'] );
+			$tax_query[] = array(
 				'taxonomy' => 'post_tag',
 				'terms'    => $q['tag_slug__in'],
 				'field'    => 'slug',
@@ -1362,7 +1388,8 @@ public function parse_tax_query( &$q ) {
 
 		if ( ! empty( $q['tag_slug__and'] ) ) {
 			$q['tag_slug__and'] = array_map( 'sanitize_title_for_query', array_unique( (array) $q['tag_slug__and'] ) );
-			$tax_query[]        = array(
+			sort( $q['tag_slug__and'] );
+			$tax_query[] = array(
 				'taxonomy' => 'post_tag',
 				'terms'    => $q['tag_slug__and'],
 				'field'    => 'slug',
@@ -2186,8 +2213,11 @@ public function get_posts() {
 			$where          .= " AND {$wpdb->posts}.post_name = '" . $q['attachment'] . "'";
 		} elseif ( is_array( $q['post_name__in'] ) && ! empty( $q['post_name__in'] ) ) {
 			$q['post_name__in'] = array_map( 'sanitize_title_for_query', $q['post_name__in'] );
-			$post_name__in      = "'" . implode( "','", $q['post_name__in'] ) . "'";
-			$where             .= " AND {$wpdb->posts}.post_name IN ($post_name__in)";
+			// Duplicate array before sorting to allow for the orderby clause.
+			$post_name__in_for_where = array_unique( $q['post_name__in'] );
+			sort( $post_name__in_for_where );
+			$post_name__in = "'" . implode( "','", $post_name__in_for_where ) . "'";
+			$where        .= " AND {$wpdb->posts}.post_name IN ($post_name__in)";
 		}
 
 		// If an attachment is requested by number, let it supersede any post number.
@@ -2199,9 +2229,14 @@ public function get_posts() {
 		if ( $q['p'] ) {
 			$where .= " AND {$wpdb->posts}.ID = " . $q['p'];
 		} elseif ( $q['post__in'] ) {
-			$post__in = implode( ',', array_map( 'absint', $q['post__in'] ) );
+			// Duplicate array before sorting to allow for the orderby clause.
+			$post__in_for_where = $q['post__in'];
+			$post__in_for_where = array_unique( array_map( 'absint', $post__in_for_where ) );
+			sort( $post__in_for_where );
+			$post__in = implode( ',', array_map( 'absint', $post__in_for_where ) );
 			$where   .= " AND {$wpdb->posts}.ID IN ($post__in)";
 		} elseif ( $q['post__not_in'] ) {
+			sort( $q['post__not_in'] );
 			$post__not_in = implode( ',', array_map( 'absint', $q['post__not_in'] ) );
 			$where       .= " AND {$wpdb->posts}.ID NOT IN ($post__not_in)";
 		}
@@ -2209,9 +2244,14 @@ public function get_posts() {
 		if ( is_numeric( $q['post_parent'] ) ) {
 			$where .= $wpdb->prepare( " AND {$wpdb->posts}.post_parent = %d ", $q['post_parent'] );
 		} elseif ( $q['post_parent__in'] ) {
-			$post_parent__in = implode( ',', array_map( 'absint', $q['post_parent__in'] ) );
+			// Duplicate array before sorting to allow for the orderby clause.
+			$post_parent__in_for_where = $q['post_parent__in'];
+			$post_parent__in_for_where = array_unique( array_map( 'absint', $post_parent__in_for_where ) );
+			sort( $post_parent__in_for_where );
+			$post_parent__in = implode( ',', array_map( 'absint', $post_parent__in_for_where ) );
 			$where          .= " AND {$wpdb->posts}.post_parent IN ($post_parent__in)";
 		} elseif ( $q['post_parent__not_in'] ) {
+			sort( $q['post_parent__not_in'] );
 			$post_parent__not_in = implode( ',', array_map( 'absint', $q['post_parent__not_in'] ) );
 			$where              .= " AND {$wpdb->posts}.post_parent NOT IN ($post_parent__not_in)";
 		}
@@ -2341,6 +2381,7 @@ public function get_posts() {
 		if ( ! empty( $q['author'] ) && '0' != $q['author'] ) {
 			$q['author'] = addslashes_gpc( '' . urldecode( $q['author'] ) );
 			$authors     = array_unique( array_map( 'intval', preg_split( '/[,\s]+/', $q['author'] ) ) );
+			sort( $authors );
 			foreach ( $authors as $author ) {
 				$key         = $author > 0 ? 'author__in' : 'author__not_in';
 				$q[ $key ][] = abs( $author );
@@ -2349,9 +2390,17 @@ public function get_posts() {
 		}
 
 		if ( ! empty( $q['author__not_in'] ) ) {
-			$author__not_in = implode( ',', array_map( 'absint', array_unique( (array) $q['author__not_in'] ) ) );
+			if ( is_array( $q['author__not_in'] ) ) {
+				$q['author__not_in'] = array_unique( array_map( 'absint', $q['author__not_in'] ) );
+				sort( $q['author__not_in'] );
+			}
+			$author__not_in = implode( ',', (array) $q['author__not_in'] );
 			$where         .= " AND {$wpdb->posts}.post_author NOT IN ($author__not_in) ";
 		} elseif ( ! empty( $q['author__in'] ) ) {
+			if ( is_array( $q['author__in'] ) ) {
+				$q['author__in'] = array_unique( array_map( 'absint', $q['author__in'] ) );
+				sort( $q['author__in'] );
+			}
 			$author__in = implode( ',', array_map( 'absint', array_unique( (array) $q['author__in'] ) ) );
 			$where     .= " AND {$wpdb->posts}.post_author IN ($author__in) ";
 		}
@@ -2588,6 +2637,7 @@ public function get_posts() {
 			if ( ! is_array( $q_status ) ) {
 				$q_status = explode( ',', $q_status );
 			}
+			sort( $q_status );
 			$r_status = array();
 			$p_status = array();
 			$e_status = array();
@@ -4902,6 +4952,33 @@ protected function generate_cache_key( array $args, $sql ) {
 		// Sort post types to ensure same cache key generation.
 		sort( $args['post_type'] );
 
+		/*
+		 * Sort arrays that can be used for ordering prior to cache key generation.
+		 *
+		 * These arrays are sorted in the query generator for the purposes of the
+		 * WHERE clause but the arguments are not modified as they can be used for
+		 * the orderby clase.
+		 *
+		 * Their use in the orderby clause will generate a different SQL query so
+		 * they can be sorted for the cache key generation.
+		 */
+		$sortable_arrays_with_int_values = array(
+			'post__in',
+			'post_parent__in',
+		);
+		foreach ( $sortable_arrays_with_int_values as $key ) {
+			if ( isset( $args[ $key ] ) && is_array( $args[ $key ] ) ) {
+				$args[ $key ] = array_unique( array_map( 'absint', $args[ $key ] ) );
+				sort( $args[ $key ] );
+			}
+		}
+
+		// Sort and unique the 'post_name__in' for cache key generation.
+		if ( isset( $args['post_name__in'] ) && is_array( $args['post_name__in'] ) ) {
+			$args['post_name__in'] = array_unique( $args['post_name__in'] );
+			sort( $args['post_name__in'] );
+		}
+
 		if ( isset( $args['post_status'] ) ) {
 			$args['post_status'] = (array) $args['post_status'];
 			// Sort post status to ensure same cache key generation.
@@ -4942,7 +5019,8 @@ static function ( &$value ) use ( $wpdb, $placeholder ) {
 			$last_changed .= wp_cache_get_last_changed( 'terms' );
 		}
 
-		return "wp_query:$key:$last_changed";
+		$this->query_cache_key = "wp_query:$key:$last_changed";
+		return $this->query_cache_key;
 	}
 
 	/**
diff --git a/tests/phpunit/tests/query/cacheResults.php b/tests/phpunit/tests/query/cacheResults.php
index 1912f69735034..84c17eb8720b9 100644
--- a/tests/phpunit/tests/query/cacheResults.php
+++ b/tests/phpunit/tests/query/cacheResults.php
@@ -200,8 +200,81 @@ public function test_generate_cache_key_unregister_post_type() {
 		$this->assertNotSame( $cache_key_1, $cache_key_2, 'Cache key should differ after unregistering post type.' );
 	}
 
+	/**
+	 * @ticket 59516
+	 *
+	 * @covers WP_Query::generate_cache_key
+	 *
+	 * @dataProvider data_orderby_clauses_are_not_normalized
+	 */
+	public function test_orderby_clauses_are_not_normalized( $query_vars1, $query_vars2 ) {
+		global $wpdb;
+
+		$this->assertArrayHasKey( 'orderby', $query_vars1, 'First query vars should have orderby.' );
+		$this->assertArrayHasKey( 'orderby', $query_vars2, 'Second query vars should have orderby.' );
+
+		$fields   = "{$wpdb->posts}.ID";
+		$query1   = new WP_Query( $query_vars1 );
+		$request1 = str_replace( $fields, "{$wpdb->posts}.*", $query1->request );
+
+		$query2   = new WP_Query( $query_vars2 );
+		$request2 = str_replace( $fields, "{$wpdb->posts}.*", $query2->request );
+
+		$reflection_q1 = new ReflectionProperty( $query1, 'query_cache_key' );
+		$reflection_q1->setAccessible( true );
+
+		$reflection_q2 = new ReflectionProperty( $query2, 'query_cache_key' );
+		$reflection_q2->setAccessible( true );
+
+		$this->assertNotSame( $request1, $request2, 'Queries should not match' );
+
+		$cache_key_1 = $reflection_q1->getValue( $query1 );
+		$cache_key_2 = $reflection_q2->getValue( $query2 );
+
+		$this->assertNotSame( $cache_key_1, $cache_key_2, 'Cache key should differ.' );
+		$this->assertNotEmpty( $cache_key_1, 'Cache key for query one should not be empty.' );
+		$this->assertNotEmpty( $cache_key_2, 'Cache key for query two should not be empty.' );
+	}
+
+	public function data_orderby_clauses_are_not_normalized() {
+		return array(
+			'orderby post__in'      => array(
+				'query_vars1' => array(
+					'post__in' => array( 1, 2, 3, 4, 5 ),
+					'orderby'  => 'post__in',
+				),
+				'query_vars2' => array(
+					'post__in' => array( 5, 4, 3, 2, 1 ),
+					'orderby'  => 'post__in',
+				),
+			),
+			'post parent in order'  => array(
+				'query_vars1' => array(
+					'post_parent__in' => array( 1, 2, 3, 4, 5 ),
+					'orderby'         => 'post_parent__in',
+				),
+				'query_vars2' => array(
+					'post_parent__in' => array( 5, 4, 3, 2, 1 ),
+					'orderby'         => 'post_parent__in',
+				),
+			),
+			'orderby post_name__in' => array(
+				'query_vars1' => array(
+					'post_name__in' => array( 'elphaba', 'glinda', 'the-wizard-of-oz', 'doctor-dillamond' ),
+					'orderby'       => 'post_name__in',
+				),
+				'query_vars2' => array(
+					'post_name__in' => array( 'doctor-dillamond', 'elphaba', 'the-wizard-of-oz', 'glinda' ),
+					'orderby'       => 'post_name__in',
+				),
+			),
+		);
+	}
+
+
 	/**
 	 * @ticket 59442
+	 * @ticket 59516
 	 *
 	 * @covers WP_Query::generate_cache_key
 	 *
@@ -217,15 +290,20 @@ public function test_generate_cache_key_normalize( $query_vars1, $query_vars2 )
 		$query2   = new WP_Query( $query_vars2 );
 		$request2 = str_replace( $fields, "{$wpdb->posts}.*", $query2->request );
 
-		$reflection = new ReflectionMethod( $query1, 'generate_cache_key' );
-		$reflection->setAccessible( true );
+		$reflection_q1 = new ReflectionProperty( $query1, 'query_cache_key' );
+		$reflection_q1->setAccessible( true );
+
+		$reflection_q2 = new ReflectionProperty( $query2, 'query_cache_key' );
+		$reflection_q2->setAccessible( true );
 
 		$this->assertSame( $request1, $request2, 'Queries should match' );
 
-		$cache_key_1 = $reflection->invoke( $query1, $query_vars1, $request1 );
-		$cache_key_2 = $reflection->invoke( $query1, $query_vars2, $request2 );
+		$cache_key_1 = $reflection_q1->getValue( $query1 );
+		$cache_key_2 = $reflection_q2->getValue( $query2 );
 
-		$this->assertSame( $cache_key_1, $cache_key_2, 'Cache key differs the same paramters.' );
+		$this->assertSame( $cache_key_1, $cache_key_2, 'Cache key differs the same effective parameters.' );
+		$this->assertNotEmpty( $cache_key_1, 'Cache key for query one should not be empty.' );
+		$this->assertNotEmpty( $cache_key_2, 'Cache key for query two should not be empty.' );
 	}
 
 	/**
@@ -280,19 +358,19 @@ public function test_query_cache( $args ) {
 	 */
 	public function data_query_cache_duplicate() {
 		return array(
-			'post type empty'           => array(
+			'post type empty'                              => array(
 				'query_vars1' => array( 'post_type' => '' ),
 				'query_vars2' => array( 'post_type' => 'post' ),
 			),
-			'post type array'           => array(
+			'post type array'                              => array(
 				'query_vars1' => array( 'post_type' => array( 'page' ) ),
 				'query_vars2' => array( 'post_type' => 'page' ),
 			),
-			'orderby empty'             => array(
+			'orderby empty'                                => array(
 				'query_vars1' => array( 'orderby' => null ),
 				'query_vars2' => array( 'orderby' => 'date' ),
 			),
-			'different order parameter' => array(
+			'different order parameter'                    => array(
 				'query_vars1' => array(
 					'post_type'      => 'post',
 					'posts_per_page' => 15,
@@ -302,31 +380,241 @@ public function data_query_cache_duplicate() {
 					'post_type'      => 'post',
 				),
 			),
-			'same args'                 => array(
+			'same args'                                    => array(
 				'query_vars1' => array( 'post_type' => 'post' ),
 				'query_vars2' => array( 'post_type' => 'post' ),
 			),
-			'same args any'             => array(
+			'same args any'                                => array(
 				'query_vars1' => array( 'post_type' => 'any' ),
 				'query_vars2' => array( 'post_type' => 'any' ),
 			),
-			'any and post types'        => array(
+			'any and post types'                           => array(
 				'query_vars1' => array( 'post_type' => 'any' ),
 				'query_vars2' => array( 'post_type' => array( 'post', 'page', 'attachment' ) ),
 			),
-			'different order post type' => array(
+			'different order post type'                    => array(
 				'query_vars1' => array( 'post_type' => array( 'post', 'page' ) ),
 				'query_vars2' => array( 'post_type' => array( 'page', 'post' ) ),
 			),
-			'post status array'         => array(
+			'non-unique post type'                         => array(
+				'query_vars1' => array( 'post_type' => array( 'post', 'page' ) ),
+				'query_vars2' => array( 'post_type' => array( 'page', 'post', 'page' ) ),
+			),
+			'post status array'                            => array(
 				'query_vars1' => array( 'post_status' => 'publish' ),
 				'query_vars2' => array( 'post_status' => array( 'publish' ) ),
 			),
-			'post status order'         => array(
+			'post status order'                            => array(
 				'query_vars1' => array( 'post_status' => array( 'draft', 'publish' ) ),
 				'query_vars2' => array( 'post_status' => array( 'publish', 'draft' ) ),
 			),
-			'cache parameters'          => array(
+			'non-unique post status'                       => array(
+				'query_vars1' => array( 'post_status' => array( 'draft', 'publish' ) ),
+				'query_vars2' => array( 'post_status' => array( 'draft', 'publish', 'draft' ) ),
+			),
+			'post id int vs string'                        => array(
+				'query_vars1' => array( 'p' => '1' ),
+				'query_vars2' => array( 'p' => 1 ),
+			),
+			'page id int vs string'                        => array(
+				'query_vars1' => array( 'page_id' => '2' ),
+				'query_vars2' => array( 'page_id' => 2 ),
+			),
+			'attachment id int vs string'                  => array(
+				'query_vars1' => array( 'attachment_id' => '3' ),
+				'query_vars2' => array( 'attachment_id' => 3 ),
+			),
+			'date and time values int vs string'           => array(
+				'query_vars1' => array(
+					'year'     => '2013',
+					'monthnum' => '12',
+					'day'      => '12',
+					'hour'     => '12',
+					'minute'   => '12',
+					'second'   => '12',
+				),
+				'query_vars2' => array(
+					'year'     => 2013,
+					'monthnum' => 12,
+					'day'      => 12,
+					'hour'     => 12,
+					'minute'   => 12,
+					'second'   => 12,
+				),
+			),
+			'offset value int vs string'                   => array(
+				'query_vars1' => array( 'offset' => '5' ),
+				'query_vars2' => array( 'offset' => 5 ),
+			),
+			'posts per page value int vs string'           => array(
+				'query_vars1' => array( 'posts_per_page' => '5' ),
+				'query_vars2' => array( 'posts_per_page' => 5 ),
+			),
+			'paged value int vs string'                    => array(
+				'query_vars1' => array( 'paged' => '2' ),
+				'query_vars2' => array( 'paged' => 2 ),
+			),
+			'menu_order value int vs string'               => array(
+				'query_vars1' => array( 'menu_order' => '2' ),
+				'query_vars2' => array( 'menu_order' => 2 ),
+			),
+			'post__in different order'                     => array(
+				'query_vars1' => array( 'post__in' => array( 1, 2, 3, 4, 5 ) ),
+				'query_vars2' => array( 'post__in' => array( 5, 4, 3, 2, 1 ) ),
+			),
+			'post__in non-unique'                          => array(
+				'query_vars1' => array( 'post__in' => array( 1, 2, 3, 4, 5 ) ),
+				'query_vars2' => array( 'post__in' => array( 1, 2, 3, 4, 5, 1, 2, 3 ) ),
+			),
+			'post_parent__in different order'              => array(
+				'query_vars1' => array( 'post_parent__in' => array( 1, 2, 3, 4, 5 ) ),
+				'query_vars2' => array( 'post_parent__in' => array( 5, 4, 3, 2, 1 ) ),
+			),
+			'post_parent__in non-unique'                   => array(
+				'query_vars1' => array( 'post_parent__in' => array( 1, 2, 3, 4, 5 ) ),
+				'query_vars2' => array( 'post_parent__in' => array( 1, 2, 3, 4, 5, 1, 2, 3 ) ),
+			),
+			'post_name__in different order'                => array(
+				'query_vars1' => array( 'post_name__in' => array( 'elphaba', 'glinda', 'the-wizard-of-oz', 'doctor-dillamond' ) ),
+				'query_vars2' => array( 'post_name__in' => array( 'doctor-dillamond', 'elphaba', 'the-wizard-of-oz', 'glinda' ) ),
+			),
+			'post_name__in non-unique'                     => array(
+				'query_vars1' => array( 'post_name__in' => array( 'elphaba', 'glinda', 'the-wizard-of-oz', 'doctor-dillamond' ) ),
+				'query_vars2' => array( 'post_name__in' => array( 'elphaba', 'glinda', 'elphaba', 'glinda', 'the-wizard-of-oz', 'doctor-dillamond' ) ),
+			),
+			'cat different order (array)'                  => array(
+				'query_vars_1' => array( 'cat' => array( '1', '2' ) ),
+				'query_vars_2' => array( 'cat' => array( '2', '1' ) ),
+			),
+			'cat different order (string)'                 => array(
+				'query_vars_1' => array( 'cat' => '2,1' ),
+				'query_vars_2' => array( 'cat' => '1,2' ),
+			),
+			'cat queries int vs string'                    => array(
+				'query_vars_1' => array( 'cat' => '2' ),
+				'query_vars_2' => array( 'cat' => 2 ),
+			),
+			'category__in queries different order (array)' => array(
+				'query_vars_1' => array( 'category__in' => array( '1', '2' ) ),
+				'query_vars_2' => array( 'category__in' => array( '2', '1' ) ),
+			),
+			'category__in queries with non-unique array'   => array(
+				'query_vars_1' => array( 'category__in' => array( '1', '1' ) ),
+				'query_vars_2' => array( 'category__in' => array( '1' ) ),
+			),
+			'category__in queries string vs array (array)' => array(
+				'query_vars_1' => array( 'category__in' => array( '1' ) ),
+				'query_vars_2' => array( 'category__in' => array( 1 ) ),
+			),
+			'category__not_in different order (array)'     => array(
+				'query_vars_1' => array( 'category__not_in' => array( '1', '2' ) ),
+				'query_vars_2' => array( 'category__not_in' => array( '2', '1' ) ),
+			),
+			'category__not_in with non-unique array'       => array(
+				'query_vars_1' => array( 'category__not_in' => array( '1', '1' ) ),
+				'query_vars_2' => array( 'category__not_in' => array( '1' ) ),
+			),
+			'category__not_in queries string vs array (array)' => array(
+				'query_vars_1' => array( 'category__not_in' => array( '1' ) ),
+				'query_vars_2' => array( 'category__not_in' => array( 1 ) ),
+			),
+			'category__and queries width different order (array)' => array(
+				'query_vars_1' => array( 'category__and' => array( '1', '2' ) ),
+				'query_vars_2' => array( 'category__and' => array( '2', '1' ) ),
+			),
+			'category__and with non-unique array'          => array(
+				'query_vars_1' => array( 'category__and' => array( '1', '1', '2' ) ),
+				'query_vars_2' => array( 'category__and' => array( '1', '2' ) ),
+			),
+			'category__and queries string vs array (array)' => array(
+				'query_vars_1' => array( 'category__and' => array( '1', '2' ) ),
+				'query_vars_2' => array( 'category__and' => array( 1, 2 ) ),
+			),
+			'author queries different order (string)'      => array(
+				'query_vars_1' => array( 'author' => '1,2' ),
+				'query_vars_2' => array( 'author' => '2,1' ),
+			),
+			'author with non-unique string'                => array(
+				'query_vars_1' => array( 'author' => '1,1' ),
+				'query_vars_2' => array( 'author' => '1' ),
+			),
+			'author queries int vs string (string)'        => array(
+				'query_vars_1' => array( 'author' => 1 ),
+				'query_vars_2' => array( 'author' => '1' ),
+			),
+			'author queries int vs string (array)'         => array(
+				'query_vars_1' => array( 'author' => array( 1 ) ),
+				'query_vars_2' => array( 'author' => array( '1' ) ),
+			),
+			'author__in different order'                   => array(
+				'query_vars_1' => array( 'author__in' => array( 1, 2 ) ),
+				'query_vars_2' => array( 'author__in' => array( 2, 1 ) ),
+			),
+			'author__in with non-unique array'             => array(
+				'query_vars_1' => array( 'author__in' => array( 1, 1, 2 ) ),
+				'query_vars_2' => array( 'author__in' => array( 1, 2 ) ),
+			),
+			'author__in queries int vs string (array)'     => array(
+				'query_vars_1' => array( 'author__in' => array( 1 ) ),
+				'query_vars_2' => array( 'author__in' => array( '1' ) ),
+			),
+			'author__not_in different order (array)'       => array(
+				'query_vars_1' => array( 'author__not_in' => array( 1, 2 ) ),
+				'query_vars_2' => array( 'author__not_in' => array( 2, 1 ) ),
+			),
+			'author__not_in queries int vs string (array)' => array(
+				'query_vars_1' => array( 'author__not_in' => array( 1 ) ),
+				'query_vars_2' => array( 'author__not_in' => array( '1' ) ),
+			),
+			'tag_slug__in order'                           => array(
+				'query_vars_1' => array( 'tag_slug__in' => array( 'foo', 'bar' ) ),
+				'query_vars_2' => array( 'tag_slug__in' => array( 'bar', 'foo' ) ),
+			),
+			'tag_slug__in non-unique vs unique'            => array(
+				'query_vars_1' => array( 'tag_slug__in' => array( 'foo', 'bar', 'bar' ) ),
+				'query_vars_2' => array( 'tag_slug__in' => array( 'foo', 'bar' ) ),
+			),
+			'tag_slug__and order'                          => array(
+				'query_vars_1' => array( 'tag_slug__and' => array( 'foo', 'bar' ) ),
+				'query_vars_2' => array( 'tag_slug__and' => array( 'bar', 'foo' ) ),
+			),
+			'tag_slug__and non-unique'                     => array(
+				'query_vars_1' => array( 'tag_slug__and' => array( 'foo', 'bar', 'foo' ) ),
+				'query_vars_2' => array( 'tag_slug__and' => array( 'bar', 'foo' ) ),
+			),
+			'tag__in queries different order (array)'      => array(
+				'query_vars_1' => array( 'tag__in' => array( 1, 2 ) ),
+				'query_vars_2' => array( 'tag__in' => array( 2, 1 ) ),
+			),
+			'tag__in queries non-unique array'             => array(
+				'query_vars_1' => array( 'tag__in' => array( 1, 2, 1 ) ),
+				'query_vars_2' => array( 'tag__in' => array( 2, 1 ) ),
+			),
+			'tag__in queries int vs string'                => array(
+				'query_vars_1' => array( 'tag__in' => array( 2, 1 ) ),
+				'query_vars_2' => array( 'tag__in' => array( '2', '1' ) ),
+			),
+			'tag__and queries different order (array)'     => array(
+				'query_vars_1' => array( 'tag__and' => array( 1, 2 ) ),
+				'query_vars_2' => array( 'tag__and' => array( 2, 1 ) ),
+			),
+			'tag__and queries non-unique array'            => array(
+				'query_vars_1' => array( 'tag__and' => array( 1, 2, 2 ) ),
+				'query_vars_2' => array( 'tag__and' => array( 2, 1 ) ),
+			),
+			'tag__not_in queries different order (array)'  => array(
+				'query_vars_1' => array( 'tag__not_in' => array( 1, 2 ) ),
+				'query_vars_2' => array( 'tag__not_in' => array( 2, 1 ) ),
+			),
+			'tag__not_in queries non-unique array'         => array(
+				'query_vars_1' => array( 'tag__not_in' => array( 1, 2, 2 ) ),
+				'query_vars_2' => array( 'tag__not_in' => array( 1, 2 ) ),
+			),
+			'tag__not_in queries int vs string (array)'    => array(
+				'query_vars_1' => array( 'tag__not_in' => array( '1' ) ),
+				'query_vars_2' => array( 'tag__not_in' => array( 1 ) ),
+			),
+			'cache parameters'                             => array(
 				'query_vars1' => array(
 					'update_post_meta_cache' => true,
 					'update_post_term_cache' => true,
diff --git a/tests/phpunit/tests/query/parseQuery.php b/tests/phpunit/tests/query/parseQuery.php
index bbf3f1217fb2e..94ced1ecd6e75 100644
--- a/tests/phpunit/tests/query/parseQuery.php
+++ b/tests/phpunit/tests/query/parseQuery.php
@@ -151,7 +151,7 @@ public function test_parse_query_cat_array_mixed() {
 			)
 		);
 
-		$this->assertSame( '1,-1', $q->query_vars['cat'] );
+		$this->assertSame( '-1,1', $q->query_vars['cat'] );
 	}
 
 	/**
diff --git a/tests/phpunit/tests/rest-api/rest-posts-controller.php b/tests/phpunit/tests/rest-api/rest-posts-controller.php
index a1b8de0474359..c42fded13222a 100644
--- a/tests/phpunit/tests/rest-api/rest-posts-controller.php
+++ b/tests/phpunit/tests/rest-api/rest-posts-controller.php
@@ -1574,7 +1574,7 @@ public function test_get_items_not_sticky_with_exclude() {
 		$this->assertNotContains( $id2, $ids );
 		$this->assertNotContains( $id3, $ids );
 
-		$this->assertPostsWhere( " AND {posts}.ID NOT IN ($id3,$id2) AND {posts}.post_type = 'post' AND (({posts}.post_status = 'publish'))" );
+		$this->assertPostsWhere( " AND {posts}.ID NOT IN ($id2,$id3) AND {posts}.post_type = 'post' AND (({posts}.post_status = 'publish'))" );
 	}
 
 	public function test_get_items_not_sticky_with_exclude_no_sticky_posts() {