Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE song (f_id VARCHAR, formats VARCHAR, resolution INTEGER)
TABLE: CREATE TABLE files (f_id VARCHAR, formats VARCHAR, resolution INTEGER)

### Question ###
What are the ids of songs that are available in either mp4 format or have resolution above 720?

### Accurate SQL ###

SELECT f_id FROM files WHERE formats = "mp4" UNION SELECT f_id FROM song WHERE resolution > 720