oracle 常用函数

join  on 

select c.*,t.codename

  from Dict_Employee c
  left join dict_code t
    on c.Emptypeid = t.Codeid

    and t.CodeTypeID='000105'

where  in 

select name from table where id in(select pid from table1)

创建视图

create or replace view rqf_ytitemhelpview2 as
select t.医保项目编码 codeid,t.项目中文名称 name,m.病种名称 note from DICT_ITEM_SYBMT t
left join DICT_SYBJBBM m on t.病种编码=m.病种编码;

除去重复项

SELECT DISTINCT Company FROM Orders

选取前几项  select * from dict_item WHERE ROWNUM <5

选择不包含某个字符串的

SELECT * FROM PersonsWHERE City NOT LIKE '%lon%