CREATE TABLE table_222666_1 (former_codes VARCHAR, new_country_names_and_codes VARCHAR)

Name the former codes for merged into panama ( pa , pan , 591 )
SELECT former_codes FROM table_222666_1 WHERE new_country_names_and_codes = "Merged into Panama ( PA , PAN , 591 )"
SELECT "former_codes" FROM "table_222666_1" WHERE "Merged into Panama ( PA , PAN , 591 )" = "new_country_names_and_codes"