How many years have an Opponent in the final of welby van horn?
CREATE TABLE table_name_74 (year INTEGER, opponent_in_the_final VARCHAR)
SELECT SUM(year) FROM table_name_74 WHERE opponent_in_the_final = "welby van horn"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_name_74 (year INTEGER, opponent_in_the_final VARCHAR) Question: How many years have an Opponent in the final of welby van horn? [/INST] SELECT SUM(year) FROM table_name_74 WHERE opponent_in_the_final = "welby van horn" </s>