Make products and rates endpoints return zero-value items (https://github.com/woocommerce/woocommerce-admin/pull/1722)

* Make products endpoint return zero-value items

* Make rates endpoint return zero-value items

* Several fixes

* Add tests

* Simplify code

* Merge both queries into one to simplify code

* Rename 'get_outer_from_sql_params' to 'get_from_sql_params'

plugins/woocommerce-admin/includes/data-stores/class-wc-admin-reports-data-store.php

@@ -606,6 +606,53 @@ class WC_Admin_Reports_Data_Store {
 		return $sql_query;
 	}
 
+	/**
+	 * Generates a virtual table given a list of IDs.
+	 *
+	 * @param array $ids Array of IDs.
+	 * @return array
+	 */
+	protected function get_ids_table( $ids ) {
+		$selects = array();
+		foreach ( $ids as $id ) {
+			array_push( $selects, "SELECT {$id} AS id" );
+		}
+		return join( ' UNION ', $selects );
+	}
+
+	/**
+	 * Returns a comma separated list of the fields in the `query_args`, if there aren't, returns `report_columns` keys.
+	 *
+	 * @param array $query_args Parameters supplied by the user.
+	 * @return array
+	 */
+	protected function get_fields( $query_args ) {
+		if ( isset( $query_args['fields'] ) && is_array( $query_args['fields'] ) ) {
+			return $query_args['fields'];
+		}
+		return array_keys( $this->report_columns );
+	}
+
+	/**
+	 * Returns a comma separated list of the field names prepared to be used for a selection after a join with `default_results`.
+	 *
+	 * @param array  $fields           Array of fields name.
+	 * @param string $id_field         Name of the column used as an identifier.
+	 * @param array  $outer_selections Array of fields that are not selected in the inner query.
+	 * @return string
+	 */
+	protected function format_join_selections( $fields, $id_field, $outer_selections = array() ) {
+		foreach ( $fields as $i => $field ) {
+			if ( $field === $id_field ) {
+				$fields[ $i ] = "default_results.id AS {$field}";
+			}
+			if ( in_array( $field, $outer_selections, true ) && array_key_exists( $field, $this->report_columns ) ) {
+				$fields[ $i ] = $this->report_columns[ $field ];
+			}
+		}
+		return implode( ', ', $fields );
+	}
+
 	/**
 	 * Fills ORDER BY clause of SQL request based on user supplied parameters.
 	 *
@@ -683,12 +730,12 @@ class WC_Admin_Reports_Data_Store {
 	}
 
 	/**
-	 * Returns comma separated ids of allowed products, based on query arguments from the user.
+	 * Returns an array of ids of allowed products, based on query arguments from the user.
 	 *
 	 * @param array $query_args Parameters supplied by the user.
-	 * @return string
+	 * @return array
 	 */
-	protected function get_included_products( $query_args ) {
+	protected function get_included_products_array( $query_args ) {
 		$included_products = array();
 		$operator          = $this->get_match_operator( $query_args );
 
@@ -710,8 +757,18 @@ class WC_Admin_Reports_Data_Store {
 			}
 		}
 
-		$included_products_str = implode( ',', $included_products );
+		return $included_products;
-		return $included_products_str;
+	}
+
+	/**
+	 * Returns comma separated ids of allowed products, based on query arguments from the user.
+	 *
+	 * @param array $query_args Parameters supplied by the user.
+	 * @return string
+	 */
+	protected function get_included_products( $query_args ) {
+		$included_products = $this->get_included_products_array( $query_args );
+		return implode( ',', $included_products );
 	}
 
 	/**

plugins/woocommerce-admin/includes/data-stores/class-wc-admin-reports-products-data-store.php

@@ -106,18 +106,6 @@ class WC_Admin_Reports_Products_Data_Store extends WC_Admin_Reports_Data_Store i
 		if ( isset( $query_args['orderby'] ) ) {
 			$sql_query['order_by_clause'] = $this->normalize_order_by( $query_args['orderby'] );
 		}
-		// Order by product name requires extra JOIN.
-		if ( false !== strpos( $sql_query['order_by_clause'], '_products' ) ) {
-			$sql_query['from_clause'] .= " JOIN {$wpdb->prefix}posts AS _products ON {$order_product_lookup_table}.product_id = _products.ID";
-		}
-
-		if ( 'postmeta.meta_value' === $sql_query['order_by_clause'] ) {
-			$sql_query['from_clause'] .= " JOIN {$wpdb->prefix}postmeta AS postmeta ON {$order_product_lookup_table}.product_id = postmeta.post_id AND postmeta.meta_key = '_sku'";
-		}
-
-		if ( 'variations' === $sql_query['order_by_clause'] ) {
-			$sql_query['from_clause'] .= " LEFT JOIN ( SELECT post_parent, COUNT(*) AS variations FROM {$wpdb->prefix}posts WHERE post_type = 'product_variation' GROUP BY post_parent ) AS _variations ON {$order_product_lookup_table}.product_id = _variations.post_parent";
-		}
 
 		if ( isset( $query_args['order'] ) ) {
 			$sql_query['order_by_clause'] .= ' ' . $query_args['order'];
@@ -128,6 +116,32 @@ class WC_Admin_Reports_Products_Data_Store extends WC_Admin_Reports_Data_Store i
 		return $sql_query;
 	}
 
+	/**
+	 * Fills FROM clause of SQL request based on user supplied parameters.
+	 *
+	 * @param array  $query_args Parameters supplied by the user.
+	 * @param string $arg_name   Name of the FROM sql param.
+	 * @param string $id_cell    ID cell identifier, like `table_name.id_column_name`.
+	 * @return array
+	 */
+	protected function get_from_sql_params( $query_args, $arg_name, $id_cell ) {
+		global $wpdb;
+		$sql_query['outer_from_clause'] = '';
+
+		// Order by product name requires extra JOIN.
+		if ( 'product_name' === $query_args['orderby'] ) {
+			$sql_query[ $arg_name ] .= " JOIN {$wpdb->prefix}posts AS _products ON {$id_cell} = _products.ID";
+		}
+		if ( 'sku' === $query_args['orderby'] ) {
+			$sql_query[ $arg_name ] .= " JOIN {$wpdb->prefix}postmeta AS postmeta ON {$id_cell} = postmeta.post_id AND postmeta.meta_key = '_sku'";
+		}
+		if ( 'variations' === $query_args['orderby'] ) {
+			$sql_query[ $arg_name ] .= " LEFT JOIN ( SELECT post_parent, COUNT(*) AS variations FROM {$wpdb->prefix}posts WHERE post_type = 'product_variation' GROUP BY post_parent ) AS _variations ON {$id_cell} = _variations.post_parent";
+		}
+
+		return $sql_query;
+	}
+
 	/**
 	 * Updates the database query with parameters used for Products report: categories and order status.
 	 *
@@ -144,7 +158,10 @@ class WC_Admin_Reports_Products_Data_Store extends WC_Admin_Reports_Data_Store i
 
 		$included_products = $this->get_included_products( $query_args );
 		if ( $included_products ) {
+			$sql_query_params                  = array_merge( $sql_query_params, $this->get_from_sql_params( $query_args, 'outer_from_clause', 'default_results.id' ) );
 			$sql_query_params['where_clause'] .= " AND {$order_product_lookup_table}.product_id IN ({$included_products})";
+		} else {
+			$sql_query_params = array_merge( $sql_query_params, $this->get_from_sql_params( $query_args, 'from_clause', "{$order_product_lookup_table}.product_id" ) );
 		}
 
 		$included_variations = $this->get_included_variations( $query_args );
@@ -175,10 +192,10 @@ class WC_Admin_Reports_Products_Data_Store extends WC_Admin_Reports_Data_Store i
 			return $order_product_lookup_table . '.date_created';
 		}
 		if ( 'product_name' === $order_by ) {
-			return '_products.post_title';
+			return 'post_title';
 		}
 		if ( 'sku' === $order_by ) {
-			return 'postmeta.meta_value';
+			return 'meta_value';
 		}
 		return $order_by;
 	}
@@ -259,7 +276,24 @@ class WC_Admin_Reports_Products_Data_Store extends WC_Admin_Reports_Data_Store i
 
 			$selections        = $this->selected_columns( $query_args );
 			$sql_query_params  = $this->get_sql_query_params( $query_args );
+			$included_products = $this->get_included_products_array( $query_args );
 
+			if ( count( $included_products ) > 0 ) {
+				$total_results = count( $included_products );
+				$total_pages   = (int) ceil( $total_results / $sql_query_params['per_page'] );
+
+				if ( 'date' === $query_args['orderby'] ) {
+					$selections .= ", {$table_name}.date_created";
+				}
+
+				$fields          = $this->get_fields( $query_args );
+				$join_selections = $this->format_join_selections( $fields, 'product_id' );
+				$ids_table       = $this->get_ids_table( $included_products, 'product_id' );
+				$prefix = "SELECT {$join_selections} FROM (";
+				$suffix = ") AS {$table_name}";
+				$right_join = "RIGHT JOIN ( {$ids_table} ) AS default_results
+					ON default_results.id = {$table_name}.product_id";
+			} else {
 				$db_records_count = (int) $wpdb->get_var(
 					"SELECT COUNT(*) FROM (
 								SELECT
@@ -276,13 +310,21 @@ class WC_Admin_Reports_Products_Data_Store extends WC_Admin_Reports_Data_Store i
 									) AS tt"
 				); // WPCS: cache ok, DB call ok, unprepared SQL ok.
 
+				$total_results = $db_records_count;
 				$total_pages   = (int) ceil( $db_records_count / $sql_query_params['per_page'] );
-			if ( $query_args['page'] < 1 || $query_args['page'] > $total_pages ) {
+
+				if ( ( $query_args['page'] < 1 || $query_args['page'] > $total_pages ) ) {
 					return $data;
 				}
 
+				$prefix     = '';
+				$suffix     = '';
+				$right_join = '';
+			}
+
 			$product_data = $wpdb->get_results(
-				"SELECT
+				"${prefix}
+					SELECT
 						{$selections}
 					FROM
 						{$table_name}
@@ -293,6 +335,9 @@ class WC_Admin_Reports_Products_Data_Store extends WC_Admin_Reports_Data_Store i
 						{$sql_query_params['where_clause']}
 					GROUP BY
 						product_id
+				{$suffix}
+					{$right_join}
+					{$sql_query_params['outer_from_clause']}
 					ORDER BY
 						{$sql_query_params['order_by_clause']}
 					{$sql_query_params['limit']}
@@ -309,7 +354,7 @@ class WC_Admin_Reports_Products_Data_Store extends WC_Admin_Reports_Data_Store i
 			$product_data = array_map( array( $this, 'cast_numbers' ), $product_data );
 			$data         = (object) array(
 				'data'    => $product_data,
-				'total'   => $db_records_count,
+				'total'   => $total_results,
 				'pages'   => $total_pages,
 				'page_no' => (int) $query_args['page'],
 			);

plugins/woocommerce-admin/includes/data-stores/class-wc-admin-reports-taxes-data-store.php

@@ -74,6 +74,33 @@ class WC_Admin_Reports_Taxes_Data_Store extends WC_Admin_Reports_Data_Store impl
 		add_action( 'woocommerce_refund_deleted', array( __CLASS__, 'sync_on_refund_delete' ), 10, 2 );
 	}
 
+	/**
+	 * Fills FROM clause of SQL request based on user supplied parameters.
+	 *
+	 * @param array  $query_args          Query arguments supplied by the user.
+	 * @param string $order_status_filter Order status subquery.
+	 * @return array                      Array of parameters used for SQL query.
+	 */
+	protected function get_from_sql_params( $query_args, $order_status_filter ) {
+		global $wpdb;
+		$table_name = $wpdb->prefix . self::TABLE_NAME;
+
+		$sql_query['from_clause']       = '';
+		$sql_query['outer_from_clause'] = '';
+
+		if ( $order_status_filter ) {
+			$sql_query['from_clause'] .= " JOIN {$wpdb->prefix}wc_order_stats ON {$table_name}.order_id = {$wpdb->prefix}wc_order_stats.order_id";
+		}
+
+		if ( isset( $query_args['taxes'] ) && ! empty( $query_args['taxes'] ) ) {
+			$sql_query['outer_from_clause'] .= " JOIN {$wpdb->prefix}woocommerce_tax_rates ON default_results.id = {$wpdb->prefix}woocommerce_tax_rates.tax_rate_id";
+		} else {
+			$sql_query['from_clause'] .= " JOIN {$wpdb->prefix}woocommerce_tax_rates ON {$table_name}.tax_rate_id = {$wpdb->prefix}woocommerce_tax_rates.tax_rate_id";
+		}
+
+		return $sql_query;
+	}
+
 	/**
 	 * Updates the database query with parameters used for Taxes report: categories and order status.
 	 *
@@ -88,20 +115,18 @@ class WC_Admin_Reports_Taxes_Data_Store extends WC_Admin_Reports_Data_Store impl
 		$sql_query_params    = $this->get_time_period_sql_params( $query_args, $order_tax_lookup_table );
 		$sql_query_params    = array_merge( $sql_query_params, $this->get_limit_sql_params( $query_args ) );
 		$sql_query_params    = array_merge( $sql_query_params, $this->get_order_by_sql_params( $query_args ) );
+		$order_status_filter = $this->get_status_subquery( $query_args );
+		$sql_query_params    = array_merge( $sql_query_params, $this->get_from_sql_params( $query_args, $order_status_filter ) );
 
 		if ( isset( $query_args['taxes'] ) && ! empty( $query_args['taxes'] ) ) {
 			$allowed_taxes                     = implode( ',', $query_args['taxes'] );
 			$sql_query_params['where_clause'] .= " AND {$order_tax_lookup_table}.tax_rate_id IN ({$allowed_taxes})";
 		}
 
-		$order_status_filter = $this->get_status_subquery( $query_args );
 		if ( $order_status_filter ) {
-			$sql_query_params['from_clause']  .= " JOIN {$wpdb->prefix}wc_order_stats ON {$order_tax_lookup_table}.order_id = {$wpdb->prefix}wc_order_stats.order_id";
 			$sql_query_params['where_clause'] .= " AND ( {$order_status_filter} )";
 		}
 
-		$sql_query_params['from_clause'] .= " JOIN {$wpdb->prefix}woocommerce_tax_rates ON {$order_tax_lookup_table}.tax_rate_id = {$wpdb->prefix}woocommerce_tax_rates.tax_rate_id";
-
 		return $sql_query_params;
 	}
 
@@ -162,9 +187,24 @@ class WC_Admin_Reports_Taxes_Data_Store extends WC_Admin_Reports_Data_Store impl
 				'page_no' => 0,
 			);
 
-			$selections       = $this->selected_columns( $query_args );
 			$sql_query_params = $this->get_sql_query_params( $query_args );
 
+			if ( isset( $query_args['taxes'] ) && ! empty( $query_args['taxes'] ) ) {
+				$total_results = count( $query_args['taxes'] );
+				$total_pages   = (int) ceil( $total_results / $sql_query_params['per_page'] );
+
+				$inner_selections = array( 'tax_rate_id', 'total_tax', 'order_tax', 'shipping_tax', 'orders_count' );
+				$outer_selections = array( 'name', 'tax_rate', 'country', 'state', 'priority' );
+
+				$selections      = $this->selected_columns( array( 'fields' => $inner_selections ) );
+				$fields          = $this->get_fields( $query_args );
+				$join_selections = $this->format_join_selections( $fields, 'tax_rate_id', $outer_selections );
+				$ids_table       = $this->get_ids_table( $query_args['taxes'], 'tax_rate_id' );
+				$prefix = "SELECT {$join_selections} FROM (";
+				$suffix = ") AS {$table_name}";
+				$right_join = "RIGHT JOIN ( {$ids_table} ) AS default_results
+					ON default_results.id = {$table_name}.tax_rate_id";
+			} else {
 				$db_records_count = (int) $wpdb->get_var(
 					"SELECT COUNT(*) FROM (
 								SELECT
@@ -181,13 +221,23 @@ class WC_Admin_Reports_Taxes_Data_Store extends WC_Admin_Reports_Data_Store impl
 								) AS tt"
 				); // WPCS: cache ok, DB call ok, unprepared SQL ok.
 
+				$total_results = $db_records_count;
 				$total_pages   = (int) ceil( $db_records_count / $sql_query_params['per_page'] );
+
 				if ( $query_args['page'] < 1 || $query_args['page'] > $total_pages ) {
 					return $data;
 				}
 
+				$selections = $this->selected_columns( $query_args );
+
+				$prefix     = '';
+				$suffix     = '';
+				$right_join = '';
+			}
+
 			$tax_data = $wpdb->get_results(
-				"SELECT
+				"{$prefix}
+						SELECT
 							{$selections}
 						FROM
 							{$table_name}
@@ -198,6 +248,9 @@ class WC_Admin_Reports_Taxes_Data_Store extends WC_Admin_Reports_Data_Store impl
 							{$sql_query_params['where_clause']}
 						GROUP BY
 							{$table_name}.tax_rate_id
+					{$suffix}
+					{$right_join}
+					{$sql_query_params['outer_from_clause']}
 					ORDER BY
 						{$sql_query_params['order_by_clause']}
 					{$sql_query_params['limit']}
@@ -212,7 +265,7 @@ class WC_Admin_Reports_Taxes_Data_Store extends WC_Admin_Reports_Data_Store impl
 			$tax_data = array_map( array( $this, 'cast_numbers' ), $tax_data );
 			$data     = (object) array(
 				'data'    => $tax_data,
-				'total'   => $db_records_count,
+				'total'   => $total_results,
 				'pages'   => $total_pages,
 				'page_no' => (int) $query_args['page'],
 			);

plugins/woocommerce-admin/tests/api/reports-products.php

@@ -84,6 +84,62 @@ class WC_Tests_API_Reports_Products extends WC_REST_Unit_Test_Case {
 		$this->assertArrayHasKey( 'product', $product_report['_links'] );
 	}
 
+	/**
+	 * Test getting reports with the `products` param.
+	 *
+	 * @since 3.5.0
+	 */
+	public function test_get_reports_products_param() {
+		wp_set_current_user( $this->user );
+		WC_Helper_Reports::reset_stats_dbs();
+
+		// Populate all of the data.
+		$product = new WC_Product_Simple();
+		$product->set_name( 'Test Product' );
+		$product->set_regular_price( 25 );
+		$product->save();
+
+		$product_2 = new WC_Product_Simple();
+		$product_2->set_name( 'Test Product 2' );
+		$product_2->set_regular_price( 25 );
+		$product_2->save();
+
+		$order = WC_Helper_Order::create_order( 1, $product );
+		$order->set_status( 'completed' );
+		$order->set_total( 100 ); // $25 x 4.
+		$order->save();
+
+		WC_Helper_Queue::run_all_pending();
+
+		$request = new WP_REST_Request( 'GET', $this->endpoint );
+		$request->set_query_params(
+			array(
+				'products'   => $product->get_id() . ',' . $product_2->get_id(),
+			)
+		);
+		$response = $this->server->dispatch( $request );
+		$reports  = $response->get_data();
+
+		$this->assertEquals( 200, $response->get_status() );
+		$this->assertEquals( 2, count( $reports ) );
+
+		$product_report = reset( $reports );
+
+		$this->assertEquals( $product->get_id(), $product_report['product_id'] );
+		$this->assertEquals( 4, $product_report['items_sold'] );
+		$this->assertEquals( 1, $product_report['orders_count'] );
+		$this->assertArrayHasKey( '_links', $product_report );
+		$this->assertArrayHasKey( 'product', $product_report['_links'] );
+
+		$product_report = next( $reports );
+
+		$this->assertEquals( $product_2->get_id(), $product_report['product_id'] );
+		$this->assertEquals( null, $product_report['items_sold'] );
+		$this->assertEquals( null, $product_report['orders_count'] );
+		$this->assertArrayHasKey( '_links', $product_report );
+		$this->assertArrayHasKey( 'product', $product_report['_links'] );
+	}
+
 	/**
 	 * Test getting reports without valid permissions.
 	 *

plugins/woocommerce-admin/tests/api/reports-taxes.php

@@ -112,6 +112,106 @@ class WC_Tests_API_Reports_Taxes extends WC_REST_Unit_Test_Case {
 		$this->assertEquals( 1, $tax_report['orders_count'] );
 	}
 
+	/**
+	 * Test getting reports with the `taxes` report.
+	 *
+	 * @since 3.5.0
+	 */
+	public function test_get_reports_taxes_param() {
+		global $wpdb;
+		wp_set_current_user( $this->user );
+		WC_Helper_Reports::reset_stats_dbs();
+
+		// Populate all of the data.
+		$product = new WC_Product_Simple();
+		$product->set_name( 'Test Product' );
+		$product->set_regular_price( 25 );
+		$product->save();
+
+		$wpdb->insert(
+			$wpdb->prefix . 'woocommerce_tax_rates',
+			array(
+				'tax_rate_id'       => 1,
+				'tax_rate'          => '7',
+				'tax_rate_country'  => 'US',
+				'tax_rate_state'    => 'GA',
+				'tax_rate_name'     => 'TestTax',
+				'tax_rate_priority' => 1,
+				'tax_rate_order'    => 1,
+			)
+		);
+
+		$wpdb->insert(
+			$wpdb->prefix . 'woocommerce_tax_rates',
+			array(
+				'tax_rate_id'       => 2,
+				'tax_rate'          => '8',
+				'tax_rate_country'  => 'CA',
+				'tax_rate_state'    => 'ON',
+				'tax_rate_name'     => 'TestTax 2',
+				'tax_rate_priority' => 1,
+				'tax_rate_order'    => 1,
+			)
+		);
+
+		$order = WC_Helper_Order::create_order( 1, $product );
+		$order->set_status( 'completed' );
+		$order->set_total( 100 ); // $25 x 4.
+		$order->save();
+
+		// @todo Remove this once order data is synced to wc_order_tax_lookup
+		$wpdb->insert(
+			$wpdb->prefix . 'wc_order_tax_lookup',
+			array(
+				'order_id'     => $order->get_id(),
+				'tax_rate_id'  => 1,
+				'date_created' => date( 'Y-m-d H:i:s' ),
+				'shipping_tax' => 2,
+				'order_tax'    => 5,
+				'total_tax'    => 7,
+			)
+		);
+
+		WC_Helper_Queue::run_all_pending();
+
+		$response = $this->server->dispatch( new WP_REST_Request( 'GET', $this->endpoint ) );
+		$request = new WP_REST_Request( 'GET', $this->endpoint );
+		$request->set_query_params(
+			array(
+				'taxes'   => '1,2',
+			)
+		);
+		$response = $this->server->dispatch( $request );
+		$reports  = $response->get_data();
+
+		$this->assertEquals( 200, $response->get_status() );
+		$this->assertEquals( 2, count( $reports ) );
+
+		$tax_report = reset( $reports );
+
+		$this->assertEquals( 2, $tax_report['tax_rate_id'] );
+		$this->assertEquals( 'TestTax 2', $tax_report['name'] );
+		$this->assertEquals( 8, $tax_report['tax_rate'] );
+		$this->assertEquals( 'CA', $tax_report['country'] );
+		$this->assertEquals( 'ON', $tax_report['state'] );
+		$this->assertEquals( 0, $tax_report['total_tax'] );
+		$this->assertEquals( 0, $tax_report['order_tax'] );
+		$this->assertEquals( 0, $tax_report['shipping_tax'] );
+		$this->assertEquals( 0, $tax_report['orders_count'] );
+
+		$tax_report = next( $reports );
+
+		$this->assertEquals( 1, $tax_report['tax_rate_id'] );
+		$this->assertEquals( 'TestTax', $tax_report['name'] );
+		$this->assertEquals( 7, $tax_report['tax_rate'] );
+		$this->assertEquals( 'US', $tax_report['country'] );
+		$this->assertEquals( 'GA', $tax_report['state'] );
+		$this->assertEquals( 7, $tax_report['total_tax'] );
+		$this->assertEquals( 5, $tax_report['order_tax'] );
+		$this->assertEquals( 2, $tax_report['shipping_tax'] );
+		$this->assertEquals( 1, $tax_report['orders_count'] );
+	}
+
 	/**
 	 * Test getting reports without valid permissions.
 	 *