oracle rename column if exists
ALTER TABLE my_table RENAME COLUMN old_name TO new_name;
-- To check if column exists before renaming it:
DECLARE
l_cnt INTEGER;
BEGIN
SELECT count(*) INTO l_cnt
FROM dba_tab_columns -- or all_tab_columns (depending on grants)
WHERE owner = 'my_schema' AND table_name = 'my_table'
AND column_name = 'my_col';
IF (l_cnt = 1) THEN
EXECUTE IMMEDIATE 'ALTER TABLE my_table
RENAME COLUMN my_col TO my_new_name';
END IF;
END;