select distinct a.comp_code,a.process_code,a.nexus_year,a.nexus_se q_no ,
a.is_audit_mail_gen , (select param_val from nexus_process_config
where param_name like 'STEP_ID') step_id
from NEXUS_TR_DATA a, nexus_process_approval_mast b where
a.is_audit_mail_gen is null OR a.is_audit_mail_gen = ' '
and b.step_id IN (step_id)
and a.process_code = b.process_code
and a.comp_code = '5655'
and a.process_code = 'ITR'
DECODE (a.comp_code ,'5655','AND (sysdate between TO_DATE('01-JAN-11') AND TO_DATE('30-JAN-11'))',
'5663', 'AND (sysdate between TO_DATE('01-FEB-11') AND TO_DATE('15-JAN-11'))')



i am facing diff in the decode part. can sum1 tel wat m i doin wrong?

Decode is not available in MySQL. Try using IF or CASE but in this case you need to write this using an OR: Also TO_DATE is not a valid function in MySQL.

you're typing with your thumbs again

this type of "language" has no place in query writing -- you're likely to make errors in your SQL syntax that way