CREATE TABLE "china_open" (
  "year_location" text,
  "mens_singles" text,
  "womens_singles" text,
  "mens_doubles" text,
  "womens_doubles" text
);

Question: Who won the mens doubles at the 2006 guangzhou event?
SQL: SELECT "mens_doubles" FROM "china_open" WHERE "year_location"='2006 Guangzhou';

Question: How many times was the womens doubles in china?
SQL: SELECT COUNT("mens_singles") FROM "china_open" WHERE "womens_doubles"='China';

Question: How many times did  li ju win the womens singles and wang liqin win the mens singles?
SQL: SELECT COUNT("womens_doubles") FROM "china_open" WHERE "womens_singles"='Li Ju' AND "mens_singles"='Wang Liqin';