case when 在线急等
select a.meansurecode,
  substr(last_day(to_date(a.statdate,'yyyy-mm-dd')), 1, 7) as statdate, 
  a.manualdatavalue,
  b.manualdatavalue,
  case 
  when a.datatype>b.datatype then 100-(a.datatype-b.datatype)/100*10 
  when a.datatype<b.datatype then 100+(b.datatype-a.datatype)/100*10 
  else a.datatype=b.datatype 
  end as score
from olap_manualdata a,
  olap_manualdata b
where a.meansurecode ='F-PA-008' 
  and a.datatype='A'
  and b.datatype='P'
  and a.meansurecode=b.meansurecode
  and a.comcode =b.comcode
  and substr(a.statdate, 1, 4) = b.statdate;
报错：ERROR: operator does not exist: character varying - character varying
LINE 6: ... when a.datatype>b.datatype then 100-(a.datatype-b.datatyp...
  ^
HINT: No operator matches the given name and argument type(s). You may need to add explicit type casts.

********** 错误 **********

ERROR: operator does not exist: character varying - character varying
SQL 状态: 42883
指导建议:No operator matches the given name and argument type(s). You may need to add explicit type casts.
字符:224


语句那里错了 ？？？


------解决方案--------------------
else a.datatype=b.datatype 这里有问题，不应该出现=判断，只能换成a的值或b的值
------解决方案--------------------

SQL code

select a.meansurecode,
  substr(last_day(to_date(a.statdate,'yyyy-mm-dd')), 1, 7) as statdate,  
  a.manualdatavalue,
  b.manualdatavalue,
  case  
  when a.datatype>b.datatype then 100-(a.datatype-b.datatype)/100*10  
  when a.datatype<b.datatype then 100+(b.datatype-a.datatype)/100*10  
  else b.datatype  
  end as score
from olap_manualdata a,
  olap_manualdata b
where a.meansurecode ='F-PA-008'  
  and a.datatype='A'
  and b.datatype='P'
  and a.meansurecode=b.meansurecode
  and a.comcode =b.comcode
  and substr(a.statdate, 1, 4) = b.statdate;

------解决方案--------------------

else a.datatype=b.datatype  想想就明白了，这个是个查询语句，
a.datatype=b.datatype是赋值语句，赋值语句应该用在Update,insert语句中。


------解决方案--------------------

SQL code
case
         when a.datatype > b.datatype then
          100 - (a.datatype - b.datatype) / 100 * 10
         when a.datatype < b.datatype then
          100 + (b.datatype - a.datatype) / 100 * 10
         else
          a.datatype = b.datatype   ---这个有问题，else已经表示除了上面两种情况，a.datatype=b.datatype被oracle看成返回部分了
       end as score

------解决方案--------------------
楼上说的对呀