增: insert t1(id, name) values(1, "alex"), (2, "wusir"), (3, "dabing")
查: select id from db1.t1 从db1库中 的t1表查询id 列
select id, name from db1.t1 查询多个字段
select * from db1.t1 查询所有
改 update db1.t1 set name = "樟树" ; : 注意,这样会修改一整列的name字段的值, 慎用
update db1.t1 set name= "alex" where id =2; 修改id=2的那条记录中name字段的值
删除: delete fromt1; 删除所有记录
delete from t1 where id = 2; 删除id=2的记录