ORA-01427. need help with the "where exists" part

i've had this error before, and have found solutions on google groups (using where exists(select null etc.)...but this is a little different because of the where clause and I'm updating from the same table. if anyone has ideas, I'd appreciate it. thanks.

I'm concatenating two columns with and adding a 0 between them, except when the month is = 10. example:

ldg_prd_desc_yr         ldg_prd_desc_mo
---------------         ---------------
2004                      2
2004                      4
2004                      8

and I want to combine the two columns to get this 200402
200404
200408

here is the query:

update prd_stat
set ldg_prd_desc =

    (select ldg_prd_desc_yr|| '0' || ldg_prd_desc_mo     from prd_stat
    where ldg_prd_desc_mo <> '10')
where exists (select null from prd_stat where ldg_prd_Desc_mo <> '10')

this is on oracle 8.1.7

thanks
MT Received on Mon May 03 2004 - 20:29:20 CDT