also try,

SELECT stk_code,trn_type,trn_date,cst_prce,str_nmbr, ;
SUM(nvl(trn_qnty,0)) AS m1_t ;
FROM test ;
WHERE MONTH(trn_date)=1 AND trn_type=1 and between(trn_date,ldStart,ldEnd) ;
GROUP BY stk_code,trn_type,trn_date,cst_prce,str_nmbr