sql从开始删除

Question

无论如何我可以将表中允许的行数限制为40，然后当添加41st时，表会删除第一行吗？

Answer 1

是的，您可以使用触发器执行此操作。您使用什么RDMS？

Answer 2

CREATE TABLE animals (
 id MEDIUMINT NOT NULL AUTO_INCREMENT,
 name CHAR(30) NOT NULL,
 PRIMARY KEY (id)
);

-- if this is 41st record, ...
-- the statement below will delete the id with 1, and so forth
insert into animals(name) values('wolverine'); 
delete from animals where id <=  LAST_INSERT_ID() - 40;