CREATE TABLE city (city_id VARCHAR, city VARCHAR)
CREATE TABLE temperature (Jan VARCHAR, city_id VARCHAR)

Give me the temperature of Shanghai in January.
SELECT T2.Jan FROM city AS T1 JOIN temperature AS T2 ON T1.city_id = T2.city_id WHERE T1.city = "Shanghai"
SELECT "T2"."Jan" FROM "city" AS "T1" JOIN "temperature" AS "T2" ON "T1"."city_id" = "T2"."city_id" WHERE "Shanghai" = "T1"."city"