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 ship ( flag VARCHAR )

### Question ###
Group by ships by flag, and return number of ships that have each flag.

### Accurate SQL ###

SELECT COUNT(*), flag FROM ship GROUP BY flag