freefly
          一門技術,如果不能講出來,那么就是沒有理解,如果不能很好的講出來,那么就是理解不夠透徹!
          posts - 9,comments - 3,trackbacks - 0
          1. create view

                    ORACLE:    CREATE OR REPLACE VIEW V_FA_ADD_CO AS

                       SQLSEVER:    IF EXISTS (SELECT 1
                                                                      FROM  sysobjects
                                                                      WHERE  idobject_id ('V_FA_ADD_CO')
                                                                       AND   type = 'V')
                                              DROP VIEW V_FA_ADD_CO;
                                              CREATE VIEW V_FA_ADD_CO AS

              
          2. the equal between join and (+)
                
                 the table(its fields stay with (+)) right  join another  corresponding   table.
                 for example: select * from a,b where a.id=b.id(+)
                         equals  select * from b rigth join a on a.id=b.id
                         equals  select * from a left join a on a.id=b.id

                  notes:join先匹配有對應的記錄,
                        (+)卻是按順序來的
           

              3. substr,substring
               
          for example: there is a table's field "userName" and it's value is "wanghuiling".
                 sqlserver: substring(userName,0,4) = "wan",substring(userName,1,4) = "wang"
                 oracle:  substr(userName,0,4)="wang",substr(userName,1,4)="wang"
             
           4. link sign
               sqlserver: "+"
              
          oracle:"||"
           
          5. update a table's some fields

               for example:there are two tables: students1 and students2

               sqlserver:update students     (can't use alias)
                             set name=s2.name,sex=s2.sex,age=s2.age,tel=s2.tel
                             from students s2 where s1.id=s2.id;
               oracle: update students1 s1
                         set (name,sex,age,tel)=
                         (select name,sex,age,tel from students2 s2 where s1.id=s2.id);

          6. Date
              for example:there are a field of  date type:input_date  and its value is 2007-08-09.   
              sqlserver : year(input_date)=2007,month(input_date)=8,day(input_date)=9
               oracle : to_char(input_date,'YYYY')=2007, to_char(input_date,'MM')=8, to_char(input_date,'DD')=9

               sDate : a java String variable
               sqlserver : input_date = '"+sDate+"' 
               oracle : input_date =  to_char( '" + sDate + "',' 'YYYY-MM-DD'')

          posted on 2006-12-31 15:42 freefly 閱讀(578) 評論(0)  編輯  收藏 所屬分類: Database
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