1) select ID from a_1c_exchange_files_new_iblock where STATUS='fail';
2) select ID from a_1c_exchange_files_orders where STATUS='fail';
3) SELECT
                IF(
                    TIMESTAMPDIFF(MINUTE, DATE_LAST_CONNECT, CURRENT_TIMESTAMP) > 90,
                    1,
                    0
                )
            FROM `a_1c_exchange_files_new_iblock` as ib
            where ib.`STATUS`="success"
            ORDER BY `DATE_LAST_CONNECT` DESC
            LIMIT 1
4) SELECT
    IF(
        HOUR(CURRENT_TIMESTAMP) BETWEEN 0 AND 8,
        0,
        (
            SELECT
                IF(
                    TIMESTAMPDIFF(HOUR, DATE_LAST_CONNECT, CURRENT_TIMESTAMP) > 0,
                    1,
                    0
                )
            FROM `a_1c_exchange_files_orders` as ib
            where ib.`STATUS`="success"
            ORDER BY `DATE_LAST_CONNECT` DESC
            LIMIT 1
        )
    ) AS `ERROR`