zergon321

create table service_pay
(
service_id ...,
transaction_id ... CHECK (transaction_id in (select id from transaction_table where type = ...)) #тип расходной транзакции
foreign key (transaction_id) references transaction(id)
);

DELIMITER //

CREATE TRIGGER service_pay_bi
BEFORE INSERT ON service_pay
FOR EACH ROW
BEGIN
IF NEW.transaction_id IN (SELECT id FROM transaction_table WHERE type = ...) THEN #указать значение события дохода
@last_error = "service_pay table can hold only the payment transactions";
CALL non_existent(); #единственный способ прервать операцию
END IF;
END//

SELECT ...
FROM tbl_1
UNION
SELECT ...
FROM tbl_2;

DECLARE size INT UNSIGNED DEFAULT ExtractingValue(xml_file, "count(//item)");
DECLARE counter INT UNSIGNED DEFAULT 1;

WHILE counter <= size DO
    INSERT INTO your_table
    VALUES
    (
    ExtractValue(xml_file, "//item[$counter]/name"),
    ExtractValue(xml_file, "//item[$counter]/photo[1]"), #элементы нумеруются с 1, а не с 0; 
    ExtractValue(xml_file, "//item[$counter]/photo[2]") #и так для всех остальных фото
    );
    SET counter = counter + 1;
END WHILE;