Bank details finding query

Validation to check whether the given bank already exists

SELECT                COUNT(*)

FROM                    (SELECT               aba.bank_account_name,

                                                                aba.bank_account_num,

                                                                aba.currency_code,

                                                                abb.bank_name,

                                                                abb.bank_branch_name,

                                                                abb.bank_num,

                                                                --abb.bank_number

                                                                abb.country         

                                FROM                    ap_bank_accounts aba,

                                                                ap_bank_branches abb

                                WHERE                abb.bank_branch_id = aba.bank_branch_id                ) BANK

WHERE                                bank_account_num  = NVL(cur_cust_bnk.bank_account_num,bank_account_num)

AND                       bank_account_name = NVL(cur_cust_bnk.bank_account_name,bank_account_name)

AND                       bank_name            = NVL(cur_cust_bnk.bank_name,bank_name)

AND                       bank_num          = NVL(cur_cust_bnk.bank_num,bank_num)

--AND                    NVL(bank_number,1)= NVL(NVL(cur_cust_bnk.bank_number,bank_number),1)

AND                       bank_branch_name  = NVL(cur_cust_bnk.bank_branch_name,bank_branch_name)

AND                       currency_code       = NVL(cur_cust_bnk.bank_account_currency_code,currency_code)

AND                       country                    = NVL(cur_cust_bnk.bank_branch_country,country);