SQL 建表

–建表
create table ADFN01 (UserID int ,
UserName varchar2(50) ,
UserSet int ,
Age int
);

–查表

select * from adfn01 ;

–增添数据

insert into adfn01 (userid,username,userset,age) values (1,‘张三’,0,25);
insert into adfn01 (userid,username,userset,age) values (2,‘李四’,1,18);
insert into adfn01 (userid,username,userset,age) values (3,‘王五’,0,21);
insert into adfn01 (userid,username,userset,age) values (4,‘赵虎’,0,19);

–删除字段

Alter table adfn01 drop column salary ;

– 新增字段

alter table adfn01 add salary number (6,2);–BINARY_DOUBLE
alter table adfn01 add reward BINARY_DOUBLE ;

case when

UPDATE adfn01 SET salary = case when age = 25 then salary +1 else salary end;
执行update语句，当age = 25 条件成立，执行then后面语句（salary + 1）否则执行else后面的（等于salary本身）。