I've this problem:

I have a view which has the following col:
cod_imm
A000-0-23232323
A000-0-23232323

B100-0-12121212
B100-0-12121212

C201-0-13131313
C312-0-14141414

I would now like that when there are duplicate codes the X (A000-X-23232323) is put, while where the code is not duplicate zero is left.

A000-0-23232323
A000-X-23232323

B100-0-12121212
B100-X-12121212

C201-0-13131313
C312-0-14141414
My attual code view is this:
CREATE OR REPLACE VIEW code_view ( SITO,
TIPO_OGG, COD_IMM, PT_SERVCO, CT_SERVCO,
DENOM_AZ, NOTE, COD_IMM_SUP, NOP,
INDIRIZZO, CAP, CODE_PROV, COMUNE,
COUNTRY, TEL_CENTR, FAX_CENTR, PIANI_ET,
SUP_COPERTA, PIANI_FT, DATA_CESSAZ, DATA_AGGIOR_AFM,
CODE_CT_UBIC, CODE_CT_COMP, DATA_FINE_UTILIZZO, COD_IMM_PRECEDENTE,
COD_IMM_SUCCESSIVO, PROPRIETA ) AS
select
AFM_COD_CONV.SITE_ID,
'A',
AFM_COD_CONV.COD_CONV||'-0-'||AFM_COD_CONV.SITE_ID,'','',
SITE.NAME DENOM_AZ,'','',
'EMS',
SITE.ADDRESS1 INDIRIZZO,
SITE.ZIP CAP,
SITE.COUNTY_ID COD_PROV,
SITE.CITY_ID COMUNE,
SITE.CTRY_ID COUNTRY,'','','','','','',
'01012003','','','','','',''
FROM AFM_COD_CONV, SITE, aree_verdi
WHERE AFM_COD_CONV.SITE_ID=SITE.SITE_ID
and SITE.SITE_ID=aree_verdi.cod_imm
GROUP BY 'AREE_VERDI',
AFM_COD_CONV.COD_CONV,
AFM_COD_CONV.SITE_ID,
SITE.NAME,
SITE.ADDRESS1,
SITE.ZIP,
SITE.COUNTY_ID,
SITE.CITY_ID,
SITE.CTRY_ID)

May be with decode on AFM_COD_CONV.COD_CONV||'-0-'||AFM_COD_CONV.SITE_ID??
Could you help me???

Thanks
Raf