Question: What country has Signed type moving from Porto?
SQL: SELECT "Country" FROM "2-12217273-5" WHERE "Type" = 'Signed' AND "Moving from" = 'Porto';

Question: Which transfer window was moving from Borussia Dortmund?
SQL: SELECT "Transfer window" FROM "2-12217273-5" WHERE "Moving from" = 'Borussia Dortmund';

Question: What is moving from ESP with transfer fee of Youth system?
SQL: SELECT "Moving from" FROM "2-12217273-5" WHERE "Country" = 'ESP' AND "Transfer fee" = 'Youth system';

Question: What is the transfer window in ESP with Promoted type and more than 2010 ends?
SQL: SELECT "Transfer window" FROM "2-12217273-5" WHERE "Country" = 'ESP' AND "Type" = 'Promoted' AND "Ends" > 2010.0;