select SYSDATE from dual
SELECT to_date( @ACCOUNT_PERIOD || '01', 'yyyymmdd') FROM dual
SELECT add_months( to_date( @ACCOUNT_PERIOD || '01', 'yyyymmdd'), -1) FROM dual
SELECT to_char(add_months( to_date( @ACCOUNT_PERIOD || '01', 'yyyymmdd'), -1),'yyyymm') FROM dual
SELECT to_date( @ACCOUNT_PERIOD || '01', 'yyyymmdd') FROM dual
SELECT add_months( to_date( @ACCOUNT_PERIOD || '01', 'yyyymmdd'), -1) FROM dual
SELECT to_char(add_months( to_date( @ACCOUNT_PERIOD || '01', 'yyyymmdd'), -1),'yyyymm') FROM dual