两种写法,正常逻辑① 插入哪张表,当不存在这个值的时候,插入这条数据insert into actorselect '3','ED','CHASE','2006-02-15 12:34:33'where not exists (select * from actor where actor_id='3') ②insert ignore会忽略数据库中已经存在 的数据,就插入新数据INSERT OR IGNORE INTO actor VALUES(3,'ED','CHASE','2006-02-15 12:34:33');