query: SELECT card_type_code ,  count(DISTINCT customer_id) FROM Customers_cards GROUP BY card_type_code
question: Are Showing all card type code and that number of customer holding card in each type.
query_toks: SELECT card_type_code , count ( DISTINCT customer_id ) FROM Customers_cards GROUP BY card_type_code
query_toks_no_value: select card_type_code , count ( distinct customer_id ) from customers_cards group by card_type_code
question_toks: Are Showing all card type code and that number of customer holding card in each type.