PARAM_COMPARE
sql_insert_caller_info(expr, PARAM_COMPARE, i, "$", info_buf);
sql_insert_caller_info(call, PARAM_COMPARE, param, printed_name, info_buf);
PARAM_COMPARE, -1, "$", info_buf);
PARAM_COMPARE, left_param, left_buf, info_buf);
select_return_states_hook(PARAM_COMPARE, &db_return_comparison);