fix(2meet-data-optimizer): join each routed group and drop the redundant GROUP BY

- posts_join joins the flat table of every routed group (a wp_core key next to a post type group no longer fails with "Unknown column")
- Flat tables are one row per post (UNIQUE post_id): remove the posts_groupby hook; skip the INNER JOIN status/date copy route for NOT EXISTS, which must match posts without a flat row
- Verify: tests/live/run.php router (9/9); qbench Q05 475 == native, no SQL error; price filter EXPLAIN has no Using temporary
- PR: PR-061

tests/integration/PostQueryRouterCopyTest.php

@@ -58,7 +58,7 @@ class PostQueryRouterCopyTest extends TestCase {
 		$mode->setValue( null, null );
 	}
 
-	/** @return array{join:string, where:string, orderby:string, groupby:string} */
+	/** @return array{join:string, where:string, orderby:string} */
 	private function sql( array $vars ): array {
 		$query = new WP_Query();
 		foreach ( array_merge(
@@ -77,7 +77,6 @@ class PostQueryRouterCopyTest extends TestCase {
 			'join'    => $router->posts_join( '', $query ),
 			'where'   => $router->posts_where( " AND wp_posts.post_status = 'publish'", $query ),
 			'orderby' => $router->posts_orderby( 'wp_posts.post_date DESC', $query ),
-			'groupby' => $router->posts_groupby( '', $query ),
 		);
 	}
 
@@ -85,7 +84,6 @@ class PostQueryRouterCopyTest extends TestCase {
 		$this->assertStringContainsString( 'LEFT JOIN', $sql['join'] );
 		$this->assertStringNotContainsString( self::ALIAS . '.`post_status`', $sql['where'] );
 		$this->assertSame( 'wp_posts.post_date DESC', $sql['orderby'] );
-		$this->assertSame( '`wp_itest_posts`.`ID`', $sql['groupby'] );
 	}
 
 	public function test_ready_copies_filter_status_and_order_by_date_on_the_flat_table(): void {
@@ -95,7 +93,6 @@ class PostQueryRouterCopyTest extends TestCase {
 		$this->assertStringContainsString( self::ALIAS . ".`post_status` IN ('publish')", $sql['where'] );
 		$this->assertStringContainsString( "wp_posts.post_status = 'publish'", $sql['where'], 'WordPress status clause stays' );
 		$this->assertSame( self::ALIAS . '.`post_date` ASC', $sql['orderby'] );
-		$this->assertSame( '', $sql['groupby'], 'one row per post: no GROUP BY, so LIMIT can stop early' );
 	}
 
 	public function test_several_explicit_statuses_are_kept(): void {
@@ -123,4 +120,9 @@ class PostQueryRouterCopyTest extends TestCase {
 		$this->assert_legacy_shape( $this->sql( array( 'post_status' => '' ) ) );
 		$this->assert_legacy_shape( $this->sql( array( 'post_status' => 'any' ) ) );
 	}
+
+	public function test_not_exists_keeps_the_legacy_shape(): void {
+		// The INNER JOIN would drop posts without a flat row, which NOT EXISTS must match.
+		$this->assert_legacy_shape( $this->sql( array( 'meta_query' => array( array( 'key' => 'rc_price', 'compare' => 'NOT EXISTS' ) ) ) ) );
+	}
 }

tests/integration/PostQueryRouterTest.php

@@ -214,6 +214,34 @@ class PostQueryRouterTest extends TestCase {
 		$this->assertStringContainsString( 'wpdo_post_wc_product', $join );
 	}
 
+	public function test_posts_join_joins_every_routed_group(): void {
+		$this->set_post_mode( 'aeav_only' );
+
+		$router = new WPDO_Post_Query_Router();
+		$query  = $this->make_query( array(
+			'post_type'  => 'product',
+			'meta_query' => array(
+				array( 'key' => '_price', 'value' => '50', 'compare' => '>=', 'type' => 'NUMERIC' ),
+				array( 'key' => '_thumbnail_id', 'compare' => 'EXISTS' ),
+			),
+		) );
+
+		$router->pre_get_posts( $query );
+		$join  = $router->posts_join( '', $query );
+		$where = $router->posts_where( '', $query );
+
+		$this->assertStringContainsString( 'wpdo_post_wc_product', $join );
+		$this->assertStringContainsString( 'wpdo_post_wp_core', $join );
+		$this->assertStringContainsString( '`wpdoflat_product_wp_core`.`_thumbnail_id` IS NOT NULL', $where );
+	}
+
+	public function test_no_group_by_is_added_for_one_row_per_post_joins(): void {
+		unset( $GLOBALS['_wp_filter_callbacks']['posts_groupby'] );
+		( new WPDO_Post_Query_Router() )->register_hooks();
+
+		$this->assertEmpty( $GLOBALS['_wp_filter_callbacks']['posts_groupby'] ?? array() );
+	}
+
 	public function test_posts_where_appends_condition_for_routed_clause(): void {
 		$this->set_post_mode( 'aeav_only' );
 

tests/live/README.md

@@ -39,7 +39,7 @@ Exit code 0 when every test passed, 1 otherwise. Output per test:
 | `shadow_write` | writes in shadow_read reach native meta (user, term, HivePress listing) |
 | `serialized` | array meta values are stored serialized in flat tables, never "Array" |
 | `resync` | dual_write / shadow_read: flat follows native after every write (4 entities × 2 modes: update, same value, delete, refused writes, stale flat, key rename by meta_id) |
-| `router` | a routed WP_Query returns the same ids, in order, as native (OR, several post types, untyped numeric compares, named orderby, LIKE) |
+| `router` | a routed WP_Query returns the same ids, in order, as native (OR, several post types, untyped numeric compares, named orderby, LIKE, keys of two groups, NOT EXISTS with the status/date copy route); routed SQL has no GROUP BY |
 | `zero_side_effect` | zone tables that were never created are never queried on save / delete |
 
 ## Tools (`tools/`)

tests/live/suites/router.php

@@ -6,7 +6,9 @@
  * out of any meta_query and ANDed them, so OR relations (Q04, Q16), queries on
  * several post types (Q08), untyped comparisons on numeric columns (Q14,
  * native compares strings) and orderby on a named clause (Q15) returned other
- * posts than WordPress would; LIKE compared without wildcards (Q06).
+ * posts than WordPress would; LIKE compared without wildcards (Q06). A key
+ * of a second group (wp_core _thumbnail_id, Q05) was never joined, and every
+ * routed query carried a GROUP BY although flat rows are one per post.
  *
  * Every case runs the same query twice on fixture posts — router hooks off,
  * then on with post mode shadow_read — and compares the ids in order.
@@ -22,7 +24,7 @@ declare(strict_types=1);
  * @param array<string, mixed> $args   Query args (meta_query, post_type, orderby …).
  * @param int[]                $ids    Fixture posts to search within.
  * @param bool                 $routed Hook a TMDO_Post_Query_Router for this query.
- * @return array{ids:int[], routed:bool}
+ * @return array{ids:int[], routed:bool, sql:string}
  */
 function tmdo_live_router_query( array $args, array $ids, bool $routed ): array {
 	global $wpdb;
@@ -46,7 +48,7 @@ function tmdo_live_router_query( array $args, array $ids, bool $routed ): array
 			)
 		);
 	} finally {
-		foreach ( array( 'pre_get_posts', 'posts_join', 'posts_where', 'posts_groupby', 'posts_orderby', 'posts_request', 'found_posts_query' ) as $hook ) {
+		foreach ( array( 'pre_get_posts', 'posts_join', 'posts_where', 'posts_orderby', 'posts_request', 'found_posts_query' ) as $hook ) {
 			$priority = has_filter( $hook, array( $router, $hook ) );
 			if ( false !== $priority ) {
 				remove_filter( $hook, array( $router, $hook ), $priority );
@@ -57,6 +59,7 @@ function tmdo_live_router_query( array $args, array $ids, bool $routed ): array
 	return array(
 		'ids'    => array_map( 'intval', $q->posts ),
 		'routed' => ! empty( $q->get( 'wpdo_post_clauses' ) ),
+		'sql'    => (string) $q->request,
 	);
 }
 
@@ -107,14 +110,22 @@ function tmdo_live_router_listings(): array {
  * @param array<string, mixed> $args          Query args.
  * @param int[]                $ids           Fixture ids.
  * @param bool|null            $expect_routed true / false to assert, null to ignore.
+ * @param bool                 $ordered       Compare order too (false when the order has ties).
  */
-function tmdo_live_router_assert_native( array $args, array $ids, ?bool $expect_routed = null ): void {
+function tmdo_live_router_assert_native( array $args, array $ids, ?bool $expect_routed = null, bool $ordered = true ): void {
 	$native = tmdo_live_router_query( $args, $ids, false );
 	$routed = tmdo_live_router_query( $args, $ids, true );
-	tmdo_live_assert_same( $native['ids'], $routed['ids'], 'routed ids (in order) vs native' );
+	if ( ! $ordered ) {
+		sort( $native['ids'] );
+		sort( $routed['ids'] );
+	}
+	tmdo_live_assert_same( $native['ids'], $routed['ids'], 'routed ids vs native' );
 	if ( null !== $expect_routed ) {
 		tmdo_live_assert_same( $expect_routed, $routed['routed'], 'query routed to the flat table' );
 	}
+	if ( $routed['routed'] ) {
+		tmdo_live_assert_true( false === stripos( $routed['sql'], 'GROUP BY' ), 'routed query adds no GROUP BY: ' . $routed['sql'] );
+	}
 }
 
 TMDO_Live::test(
@@ -246,3 +257,43 @@ TMDO_Live::test(
 		}
 	}
 );
+
+TMDO_Live::test(
+	'Q05 keys of two groups are both joined, routed',
+	static function () {
+		$l = tmdo_live_router_listings();
+		TMDO_Live_Fixtures::field( 'post', '_thumbnail_id', 'hp_listing' );
+		update_post_meta( $l['L1'], '_thumbnail_id', '123' );
+		update_post_meta( $l['L3'], '_thumbnail_id', '124' );
+		tmdo_live_router_assert_native(
+			array(
+				'post_type'  => 'hp_listing',
+				'meta_query' => array(
+					array( 'key' => 'hp_hourly_rate', 'value' => 42, 'compare' => '>=', 'type' => 'NUMERIC' ),
+					array( 'key' => '_thumbnail_id', 'compare' => 'EXISTS' ),
+				),
+			),
+			array_values( $l ),
+			true
+		);
+	}
+);
+
+TMDO_Live::test(
+	'NOT EXISTS with explicit statuses and date order keeps posts without a flat row',
+	static function () {
+		$l = tmdo_live_router_listings();
+		tmdo_live_router_assert_native(
+			array(
+				'post_type'   => 'hp_listing',
+				'post_status' => array( 'draft' ),
+				'orderby'     => 'date',
+				'order'       => 'DESC',
+				'meta_query'  => array( array( 'key' => 'hp_featured', 'compare' => 'NOT EXISTS' ) ),
+			),
+			array_values( $l ),
+			true,
+			false
+		);
+	}
+);