如果是合格律100%得分就是60分，否则每低0.1个百分点扣一分，存储过程如何写

create table t1 (col1 varchar(10));insert into t1 values ('96%');insert into t1 values ('90%');insert into t1 values ('100%');insert into t1 values ('88%');insert into t1 values ('34%');insert into t1 values ('77%');select col1,case when substr(col1,1,length(col1)-1)-40 >=0 then substr(col1,1,length(col1)-1)-40 else 0 end scorefrom t1      col1     score-------------------------1    96%    562    90%    503    100%    604    88%    485    34%    06    77%    37