Expose MySQL affected row counts

src/wasm/core.cpp

@@ -280,6 +280,7 @@ static bool wasm_mysql_has_unquoted_positional_placeholder(String query)
 
 DValue MySQL::query(String q)
 {
+	affected_rows = 0;
 	if(wasm_mysql_has_unquoted_positional_placeholder(q))
 	{
 		_preload_next_error_code = 2000;