oracle中的update多表关联

Question

用 tb_cd_inforlistletter表中的列 cd_uid 更新  tb_dagl_inforbook   表中的列 INFOR_SORT；条件是tb_cd_inforlistletter  A,  tb_dagl_inforbook B   WHERE     TRIM(A.CD_NAME) = TRIM(B.INFOR_TYPE)  ；

Answer 1

update tb_dagl_inforbook b set
  infor_sort=(select cd_uid from tb_cd_inforlistletter where TRIM(CD_NAME) = TRIM(B.INFOR_TYPE))

Answer 2

update tb_dagl_inforbook b 
set    b.INFOR_SORT = (select a.cd_uid 
                       from   tb_cd_inforlistletter a 
                       where  trim(a.cd_name) = trim(b.infor_type)
                      )
where  exists (select  1 
               from    tb_cd_inforlistletter 
               where   trim(cd_name) = trim(b.infor_type)
              );

Answer 3

我也复制一个update tb_dagl_inforbook b set 
         infor_sort = (
                         select cd_uid 
                         from   tb_cd_inforlistletter a
                         where TRIM(a.CD_NAME) = TRIM(b.INFOR_TYPE)
                       );