create table operations(
Id integer unsigned not null auto_increment,
Investor integer unsigned not null default 0, #Номер инвестора (0 - управляющий)
Delta Dec(11, 2) not null,                    #Сумма операции
Data date default null,                       #Дата операции
primary key (Id));

delimiter !!

create trigger operations_insert
before insert on operations
for each row
begin
  declare D Date;

  declare Cur cursor for
    select Delta, Data from operations
    where Investor = 0;

  select Min(Data) from operations
  where Investor = new.Investor
  into D;

  open Cur;
  while D <= new.Data do

    fetch Cur into T, D;

  end while;
  close Cur;

end !!

delimiter ;

insert into operations(Investor, Delta) values(1, 1000);
insert into operations(Investor, Delta) values(2, 500);

insert into operations(Delta) values(100);

insert into operations(Investor, Delta) values(1, -1050);