orcle學習之路第二天

1.Order by:
select * from zybrxx order by zyh asc
Select * from zybrxx order by zyh desc
select zyh, brxm,bqh from zybrxx order by bqh,zyh
select zyh, brxm,bqh from zybrxx order by zyh,bqh
select zyh, brxm,bqh from zybrxx order by bqh asc,zyh desc
select * from zybq order by dm desc ,lc asc
2.Group by:select count(*) from zybrxx group by bqh
SQL 無法把正常的列和彙總函數結合在一起
select count(*),zyh from zybrxx group by bqh//會提示錯誤
無論在什麼情況下進行分組 SELECT 語句中出現的字段只能是在 GROUP BY中出現過的纔可以 ——除非你在 SELECT 子句中不指定任何字段
3.Having:select sum(zfze) from zybrxx group by zfze having sum(zfze)>0
表的聯合：
4.在一個sql中使用多個表：交叉聯合select * from ksmc,zybq
select no,xh,dm from ksmc,zybq
5.等值聯合：select * from zybrxx a,ksmc b where b.no = a.ksbh and a.ksbh<2
6.不等值聯合：select * from zybrxx a,ksmc b where b.no > a.ksbh
7.select * from zybrxx a join ksmc b on a.ksbh=b.no那個表在前就以那個表爲主
8.右聯接：select * from ksmc b right outer join zybrxx a on a.ksbh =b.no
9.左聯接：select * from ksmc b left outer join zybrxx a on a.ksbh =b.no
內嵌的sql子句
10.select * from zybrxx a,ksmc b where a.ksbh=(select no from ksmc where mc=’內科’ ) and a.ksbh =b.no
11.子查詢的嵌套：select * from zybrxx a,ksmc b where a.ksbh=(select no from ksmc where mc=(select mc from ksmc where no=1 )) and a.ksbh =b.no
操作數據
12.插入語句Insert values：insert into zybq(dm,mc,qx,dnfykf,bqfl,lc,srm1,srm2,cwyybz) values(‘12’,’病區2’,’**’,’02’,0,666,’88BQ’,’88UA’,’Y’)
插入空值：insert into zybq(dm,mc,qx,dnfykf,bqfl,lc,yzysl,srm1,srm2,cwyybz) values(‘15’,’病區2’,’**’,’02’,0,666,”,’88BQ’,’88UA’,’Y’)
Insert select:insert into new_table select * from zybq//可完成對錶的備份
13.Update:update zybq set mc=’病區2眼科’ where dm=’15’
對多個列進行更新：update zybq set mc=’病區2眼科’,qx=’*’ where dm=’15’
不加條件全部更新：update zybq set qx=’**’
允許其他數值對數據進行修改：update zybq set yzysl=yzysl-1
14.Delete:delete from zybq where dm=’15’