2015.7.17 case when then else end用法Oralcle与SQLserver一致

SELECT  

CASE airway_point_type_id

WHEN 1 THEN 'VOR'

WHEN 2 THEN 'VOR/DME'

WHEN 3 THEN 'NDB'

WHEN 10 THEN 'P字点'

WHEN 11 THEN '五字代码点'

ELSE '其它' END

航路点类型

FROM AIRWAY_POINT

GROUP BY AIRWAY_POINT_TYPE_ID

或者

select
            case when max(sup_no) is null or to_number(to_char(sysdate,'yyyy')||'01')> max(sup_no)
                      then to_number(to_char(sysdate,'yyyy')||'01')
                      else max(sup_no)+1        
                      end nextcur
            from EX_VERSION

或者

select

case when g.val_rnp<0

then 'RNAV '|| to_char(0-g.val_rnp)

when g.val_rnp>=0 then 'RNP '|| to_char(g.val_rnp)

else ''

end RNP值

case when的嵌套用法

case when g.val_rnp<0 then
                   case when 0-g.val_rnp <1 then 'RNAV '|| to_char(0-g.val_rnp,'0.9')
                   else 'RNAV '|| to_char(0-g.val_rnp) end
         when g.val_rnp>=0 then
                  case when g.val_rnp <1 then 'RNP '|| to_char(g.val_rnp,'0.9')
                  else 'RNP '|| to_char(g.val_rnp) end
         else '' end RNP值,