oracle decode case语法

SELECT col1, col2,   

       CASE   

          WHEN col3 > 1 AND col3 <2   

             THEN '1'   

          WHEN col3 > 2 AND col3 <3   

             THEN '2'   

          WHEN col3 > 3 AND col3 <4   

             THEN '3'   

          ELSE '4'   

       END mylevel   

FROM table   

  

select case   

       when    nsrsbh='330165737758262'   then   nsrsbh  

       when    nsrsbh='330106745808709'    then   nsrsbh   

       else     '99999'  

       end   

from WS_TDS_SQ  

select case    nsrsbh

       when   '330165737758262'  then  nsrsbh  

       when   '330106745808709'    then   nsrsbh   

       else    '99999'  

       end   

from table  

  

decode(条件,值1,返回值1,值2,返回值2,...值n,返回值n,缺省值)  

decode(字段或字段的运算，值1，值2，值3）  

select decode (value, <if this value>, <return this value>) FROM table  

  

select decode(col1,'330165737758262',nsrsbh,'330106745808709',nsrsbh,0) from table 

select decode(col1,'330165737758262','6','9') from table