Select information_schema using a nested query

TODO:
- support WHERE, ORDER...
- support AS
- ensure all schema fields are correct

Author: bgrgicak

tests/WP_SQLite_Metadata_Tests.php

@@ -73,6 +73,36 @@ public function testCountTables() {
 		self::assertIsNumeric( $count );
 	}
 
+	public function testInformationSchemaTables() {
+		$result = $this->assertQuery( "SELECT * FROM information_schema.tables" );
+		$this->assertEquals(
+			array(
+				'TABLE_NAME' => '_mysql_data_types_cache',
+				'TABLE_TYPE' => 'BASE TABLE',
+				'TABLE_SCHEMA' => 'database',
+				'ENGINE' => 'InnoDB',
+				'TABLE_COLLATION' => 'utf8mb4_general_ci',
+				'TABLE_COMMENT' => '',
+				'CREATE_TABLE' => 'CREATE TABLE _mysql_data_types_cache (
+		`table` TEXT NOT NULL,
+		`column_or_index` TEXT NOT NULL,
+		`mysql_type` TEXT NOT NULL,
+		PRIMARY KEY(`table`, `column_or_index`)
+	)',
+				'AUTO_INCREMENT' => null,
+				'CREATE_TIME' => null,
+				'UPDATE_TIME' => null,
+				'CHECK_TIME' => null,
+				'TABLE_ROWS' => '0',
+				'DATA_LENGTH' => '0',
+				'INDEX_LENGTH' => '0',
+				'DATA_FREE' => '0',
+				'VERSION' => '10',
+			),
+			(array) $result[0]
+		);
+	}
+
 	private function assertQuery( $sql, $error_substring = null ) {
 		$retval = $this->engine->query( $sql );
 		if ( null === $error_substring ) {

wp-includes/sqlite/class-wp-sqlite-translator.php

@@ -1508,9 +1508,37 @@ private function execute_select() {
 		$updated_query = $this->rewriter->get_updated_query();
 
 		if ( $table_name && str_starts_with( strtolower( $table_name ), 'information_schema' ) ) {
-			$this->is_information_schema_query = true;
-			$updated_query                     = $this->get_information_schema_query( $updated_query );
-			$params                            = array();
+			// $this->is_information_schema_query = true;
+			// $updated_query                     = $this->get_information_schema_query( $updated_query );
+			// $params                            = array();
+			$updated_query = str_replace(
+				$table_name.'.tables',
+				"(SELECT
+					name as TABLE_NAME,
+					'database' as TABLE_SCHEMA,
+					CASE type
+					WHEN 'table' THEN 'BASE TABLE'
+					WHEN 'view' THEN 'VIEW'
+					ELSE type
+					END as TABLE_TYPE,
+					'InnoDB' as ENGINE,
+					'utf8mb4_general_ci' as TABLE_COLLATION,
+					'' as TABLE_COMMENT,
+					sql as CREATE_TABLE,
+					NULL as AUTO_INCREMENT,
+					NULL as CREATE_TIME,
+					NULL as UPDATE_TIME,
+					NULL as CHECK_TIME,
+					0 as TABLE_ROWS,
+					0 as DATA_LENGTH,
+					0 as INDEX_LENGTH,
+					0 as DATA_FREE,
+					10 as VERSION
+					FROM sqlite_master
+					WHERE type IN ('table', 'view'))",
+				$updated_query
+			);
+			var_dump( $updated_query );
 		} elseif (
 			// Examples: @@SESSION.sql_mode, @@GLOBAL.max_allowed_packet, @@character_set_client
 			preg_match( '/@@((SESSION|GLOBAL)\s*\.\s*)?\w+\b/i', $updated_query ) === 1 ||
@@ -3271,7 +3299,7 @@ private function execute_alter() {
 						new WP_SQLite_Token( ' ', WP_SQLite_Token::TYPE_WHITESPACE ),
 						new WP_SQLite_Token( 'ON', WP_SQLite_Token::TYPE_KEYWORD, WP_SQLite_Token::FLAG_KEYWORD_RESERVED ),
 						new WP_SQLite_Token( ' ', WP_SQLite_Token::TYPE_WHITESPACE ),
-						new WP_SQLite_Token( '"' . $this->table_name . '"', WP_SQLite_Token::TYPE_STRING, WP_SQLite_Token::FLAG_STRING_DOUBLE_QUOTES ),
+						new WP_SQLite_Token( "\"$this->table_name\"", WP_SQLite_Token::TYPE_STRING, WP_SQLite_Token::FLAG_STRING_DOUBLE_QUOTES ),
 						new WP_SQLite_Token( ' ', WP_SQLite_Token::TYPE_WHITESPACE ),
 						new WP_SQLite_Token( '(', WP_SQLite_Token::TYPE_OPERATOR ),
 					)