Sqlite3, the practice in Wikipedia:

Https://en.wikibooks.org/wiki/SQL_Exercises/The_computer_store

Two tables connected to each other

Manufactures: code, name

Products:code, name, Price, manufacturer

Yellow is an association.

Select the name and price of the cheapest product.

?? : Use nested structure, so that you can get all the cheapest prices of products, product prices if there is the same.

If you write only the code within the substructure, you can return only one row.

select    price  from  products  where  price  =   ( select  min   ( price  )  from  products  );   

A. Select the name of each manufacturer along with the name and price of their most expensive product. Not very understanding; /c1>

   SELECT A.Name, A. Price, F.Name    from  Products A INNER JOIN Manufacturers F    on A.manufacturer = F.Code      and A. Price =     (       SELECT MAX(A. Price)          from  Products A         WHERE A.manufacturer = F.Code     );

Sqlite3, the practice in Wikipedia: