CREATE TABLE table_69731 ("Outcome" CLOB, "Date" CLOB, "Surface" CLOB, "Partner" CLOB, "Opponents" CLOB, "Score" CLOB)

What was the Surface for the Partner of J rgen Melzer, and a Date of July 16, 2011?
SELECT "Surface" FROM table_69731 WHERE "Partner" = 'jürgen melzer' AND "Date" = 'july 16, 2011'
SELECT "Surface" FROM "table_69731" WHERE "Date" = 'july 16, 2011' AND "Partner" = 'jürgen melzer'