Allow custom mysql flags for db exec command

See #548

inc/composer/class-command.php

@@ -679,7 +679,11 @@ protected function db( InputInterface $input, OutputInterface $output ) {
 
 				break;
 			case 'exec':
-				$query = $input->getArgument( 'options' )[1] ?? null;
+				$options = $input->getArgument( 'options' ) ?? [];
+				array_shift( $options ); // remove the subcommand, we don't need it
+				$query = array_pop( $options ) ?: null; // the query is always the last option
+				$args = count( $options ) > 1 ? implode( ' ', $options ) : ''; // implode all optional options
+
 				if ( empty( $query ) ) {
 					$output->writeln( '<error>No query specified: pass a query via `db exec -- "sql query..."`</error>' );
 					break;
@@ -688,7 +692,7 @@ protected function db( InputInterface $input, OutputInterface $output ) {
 					$query = "$query;";
 				}
 				// phpcs:ignore WordPress.WP.CapitalPDangit.Misspelled
-				passthru( "$base_command mysql --database=wordpress --user=root -e \"$query\"", $return_val );
+				passthru( "$base_command mysql --database=wordpress --user=root $args -e \"$query\"", $return_val );
 				break;
 			case null:
 				// phpcs:ignore WordPress.WP.CapitalPDangit.Misspelled