Urgent ---group by syntax error

Question

This is my syntax as below.But it doesn't work.Does anyone can tell me what's problem ? or it have another way to solve this quuestion? thanks .
sql syntax:
select a.txdate,a.costype,sum(cosamt) * (1+a.cosrate) as costamount
from sales_cost a
where a.txdate between '2003-01-01' and '2003-02-01'
group by a.txdate,a.costype;

Answer 1

Although more specifics might have helped, I am assuming based on the title of the post: "urgent ---group by syntax error" and my test of the original code that I have identified the error. See the example below for how the original code produces a group by error and how the solution I provided executes without error.
SQL> -- test data:
SQL> SELECT * FROM sales_cost
  2  /
TXDATE      COSTYPE    COSAMT   COSRATE                                                            
03-JAN-03         1         3        .5                                                            
03-JAN-03         1         4       .25                                                            
03-JAN-03         2         4       .75                                                            
04-JAN-03         3         3        .5                                                            
04-JAN-03         4         4       .25                                                            
04-JAN-03         4         4       .75                                                            
6 rows selected.
SQL> --
SQL> --
SQL> -- wrong:
SQL> SELECT   a.txdate, a.costype,
  2             SUM (a.cosamt) * (1 + a.cosrate) AS costamount
  3  FROM     sales_cost a
  4  WHERE    a.txdate BETWEEN '2003-01-01' AND '2003-02-01'
  5  GROUP BY a.txdate,a.costype
  6  /
         SUM (a.cosamt) * (1 + a.cosrate) AS costamount
ERROR at line 2:
ORA-00979: not a GROUP BY expression
SQL> --
SQL> --
SQL> -- correct:
SQL> SELECT   a.txdate, a.costype,
  2             SUM (a.cosamt * (1 + a.cosrate)) AS costamount
  3  FROM     sales_cost a
  4  WHERE    a.txdate BETWEEN TO_DATE ('2003-01-01', 'YYYY-MM-DD')
  5                   AND     TO_DATE ('2003-02-01', 'YYYY-MM-DD')
  6  GROUP BY a.txdate,a.costype
  7  /
TXDATE      COSTYPE COSTAMOUNT                                                                     
03-JAN-03         1        9.5                                                                     
03-JAN-03         2          7                                                                     
04-JAN-03         3        4.5                                                                     
04-JAN-03         4         12