Question: Show the builder of railways associated with the trains named "Andaman Exp".
Schema: create table railway (builder varchar, railway_id varchar, PRIMARY KEY (builder)); create table train (railway_id varchar, name varchar, PRIMARY KEY (railway_id))
SQL: select t1.builder from railway as t1 join train as t2 on t1.railway_id = t2.railway_id where t2.name = "andaman exp"