Declare
	     Cursor Cur1 is    SELECT   slcode, 
                                               vendname,
                                               vendtdsperc,
                                               glcode, 
                                               Sum(debitamount) - [B]Nvl((SELECT Sum(creditamount) 
                                                                       FROM   ledger  
                                                                       WHERE  a.unitid = 1 
                                                                              AND a.periodid = 12 
                                                                              AND a.slcode = b.slcode 
                                                                              AND a.glcode = b.glcode 
                                                                              AND Substr(a.documentno,2,3) = '207'),0) derval [/B]
                                      FROM     ledger b, 
                                               vendmast c 
                                      WHERE    b.unitid = 1 
                                               AND b.periodid = 12 
                                               AND Substr(b.documentno,2,3) = '212' 
                                               AND b.glcode NOT IN ('61118','61129','61210') 
                                               AND b.debitamount <> 0 
                                               AND b.slcode = c.vendcode 
                                      GROUP BY slcode, 
                                               glcode,
                                               vendtdsperc, 
                                               vendname;
Begin
	Null;
End;

Error follows

Error 103 at line 30 column 72
   Encountered the symbol "SELECT" when expecting one of the following
(- + mod not null others <an identifier>
<a double-quoted delimited-identifier> <a bind variable> avg
count current exists max min prior sql stddev sum variance
cast < a string literal with character set specification>
<a number><a single-quoted SQL string>

Error 103 at line 36, column 116

Encountered the symbol "," When expecting one of the following:

)intersect minus union

Nvl((SELECT Sum(creditamount) 
                                                                       FROM   ledger a 
                                                                       WHERE  a.unitid = 1 
                                                                              AND a.periodid = 12 
                                                                              AND a.slcode = b.slcode 
                                                                              AND a.glcode = b.glcode 
                                                                              AND Substr(a.documentno,2,3) = '207'), 
                                                                      0) derval