Show all card type codes and the number of customers holding cards in each type.
CREATE TABLE Customers_cards (card_type_code VARCHAR, customer_id VARCHAR)
SELECT card_type_code, COUNT(DISTINCT customer_id) FROM Customers_cards GROUP BY card_type_code
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE Customers_cards (card_type_code VARCHAR, customer_id VARCHAR) Question: Show all card type codes and the number of customers holding cards in each type. [/INST] SELECT card_type_code, COUNT(DISTINCT customer_id) FROM Customers_cards GROUP BY card_type_code </s>