SQL> select certificate_nbr,
2 part171,
3 inactive_ind,
4 hts_cde,
5 originating_ind,
6 iso_country_cde,
7 basis_cde,
8 producer_cde,
9 cert_cde,
10 regional_value_content_cde,
11 part_nbr,
12 effective_date,
13 effective_from_date,
14 effective_to_date,
15 transaction_date
16 from SAP_CERTIFICATES_EXTRACT_VIEW
17 where org_id= '0048' AND
18 customer_nbr_base= '00000065' AND
19 customer_nbr_sufx = '11' AND
20 to_char(EFFECTIVE_FROM_DATE , 'YY')='04' AND
21 to_char(EFFECTIVE_TO_DATE, 'yy')='04';

Error
to_char(EFFECTIVE_FROM_DATE , 'YY')='04' AND
*
ERROR at line 20:
ORA-01722: invalid number

all spelling are correct... to_char is correct..... date formate is correct.... bit why there is an error is the question...

though i tried it on other table in same way it worked
select to_char(effective_dte, 'mm-dd-yy'),
to_char(expiration_dte, 'mm-dd-yy'), org_id
from certificates
where to_char(effective_dte, 'yy')='04'

what can possible be wrong...??

-NBSR