What is the name of a partner that played on a hard surface on 18 April 2011?
CREATE TABLE table_name_23 (partner VARCHAR, surface VARCHAR, date VARCHAR)
SELECT partner FROM table_name_23 WHERE surface = "hard" AND date = "18 april 2011"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_name_23 (partner VARCHAR, surface VARCHAR, date VARCHAR) Question: What is the name of a partner that played on a hard surface on 18 April 2011? [/INST] SELECT partner FROM table_name_23 WHERE surface = "hard" AND date = "18 april 2011" </s>