SELECT count(DISTINCT Currency_Code) FROM Drama_Workshop_Groups
How many distinct currency codes are there for all drama workshop groups?
[Schema (values) (types)]: | cre_Drama_Workshop_Groups |  Ref_Payment_Methods : payment_method_code (text) , payment_method_description (text) | Ref_Service_Types : service_type_code (text) , parent_service_type_code (text) , service_type_description (text) | Addresses : address_id (text) , line_1 (text) , line_2 (text) , city_town (text) , state_county (text) , other_details (text) | Products : product_id (text) , product_name (text) , product_price (text) , product_description (text) , other_product_service_details (text) | Marketing_Regions : marketing_region_code (text) , marketing_region_name (text) , marketing_region_descriptrion (text) , other_details (text) | Clients : client_id (text) , address_id (text) , customer_email_address (text) , customer_name (text) , customer_phone (text) , other_details (text) | Drama_Workshop_Groups : workshop_group_id (text) , address_id (text) , currency_code (text) , marketing_region_code (text) , store_name (text) , store_phone (text) , store_email_address (text) , other_details (text) | Performers : performer_id (text) , address_id (text) , customer_name (text) , customer_phone (text) , customer_email_address (text) , other_details (text) | Customers : customer_id (text) , address_id (text) , customer_name (text) , customer_phone (text) , customer_email_address (text) , other_details (text) | Stores : store_id (text) , address_id (text) , marketing_region_code (text) , store_name (text) , store_phone (text) , store_email_address (text) , other_details (text) | Bookings : booking_id (text) , customer_id (text) , workshop_group_id (text) , status_code (text) , store_id (text) , order_date (text) , planned_delivery_date (text) , actual_delivery_date (text) , other_order_details (text) | Performers_in_Bookings : order_id (text) , performer_id (text) | Customer_Orders : order_id (text) , customer_id (text) , store_id (text) , order_date (text) , planned_delivery_date (text) , actual_delivery_date (text) , other_order_details (text) | Order_Items : order_item_id (text) , order_id (text) , product_id (text) , order_quantity (text) , other_item_details (text) | Invoices : invoice_id (text) , order_id (text) , payment_method_code (text) , product_id (text) , order_quantity (text) , other_item_details (text) , order_item_id (text) | Services : service_id (text) , service_type_code (text) , workshop_group_id (text) , product_description (text) , product_name (text) , product_price (text) , other_product_service_details (text) | Bookings_Services : order_id (text) , product_id (text) | Invoice_Items : invoice_item_id (text) , invoice_id (text) , order_id (text) , order_item_id (text) , product_id (text) , order_quantity (text) , other_item_details (text);