SQL> select * from aa;

        BB         CC
---------- ----------
         1  999999.99

SQL> col bb format ''''99.9'''';
SQL> select * from aa;

   BB         CC
----- ----------
  1.0  999999.99

SQL> col bb head ''''99.9'''';
SQL> select * from aa;

 99.9         CC
----- ----------
  1.0  999999.99

SQL> col bb head ''''学号'''';
SQL> select * from aa;

 学号         CC
----- ----------
  1.0  999999.99

SQL> col bb format ''''99'''';
SQL> select * from aa;

学号         CC
---- ----------
   1  999999.99

SQL> col bb head ''''学|号'''';
SQL> select * from aa;

 学
 号         CC
--- ----------
  1  999999.99

SQL> select count(bb),sum(cc) from aa;

 COUNT(BB)    SUM(CC)
---------- ----------
      8192 8191999918

SQL> col sum(cc) format ''''9999999999.99'''';
SQL> select count(bb),sum(cc) from aa;

 COUNT(BB)        SUM(CC)
---------- --------------
      8192  8191999918.08

SQL> col sum(cc) format ''''9999999999.99'''' head ''''总分'''';
SQL> col count(bb) format ''''999999'''' head ''''人数'''';
SQL> select count(bb),sum(cc) from aa;

   人数           总分
------- --------------
   8192  8191999918.08