Name the surface for philadelphia
CREATE TABLE table_23235767_4 (surface VARCHAR, championship VARCHAR)
SELECT surface FROM table_23235767_4 WHERE championship = "Philadelphia"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_23235767_4 (surface VARCHAR, championship VARCHAR) Question: Name the surface for philadelphia [/INST] SELECT surface FROM table_23235767_4 WHERE championship = "Philadelphia" </s>