When vista radio is the owner how many call signs are there?
CREATE TABLE table_18536769_1 (call_sign VARCHAR, owner VARCHAR)
SELECT COUNT(call_sign) FROM table_18536769_1 WHERE owner = "Vista Radio"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_18536769_1 (call_sign VARCHAR, owner VARCHAR) Question: When vista radio is the owner how many call signs are there? [/INST] SELECT COUNT(call_sign) FROM table_18536769_1 WHERE owner = "Vista Radio" </s>