gistfile1.txt

>> Book.select(:author, :isbn).first
  Book Load (0.4ms)  SELECT  "books"."author", "books"."isbn" FROM "books" ORDER BY "books"."id" ASC LIMIT $1  [["LIMIT", 1]]
=> #<Book id: nil, isbn: "0787967076", author: "Steven B. Sample">
>> Book.select(:id, :author, :isbn).first
  Book Load (0.3ms)  SELECT  "books"."id", "books"."author", "books"."isbn" FROM "books" ORDER BY "books"."id" ASC LIMIT $1  [["LIMIT", 1]]
=> #<Book id: 5, isbn: "0787967076", author: "Steven B. Sample">
>> Book.find(5).update(isbn: nil, author: "heyo")
  Book Load (0.5ms)  SELECT  "books".* FROM "books" WHERE "books"."id" = $1 LIMIT $2  [["id", 5], ["LIMIT", 1]]
   (0.1ms)  BEGIN
  SQL (19.7ms)  UPDATE "books" SET "isbn" = $1, "author" = $2, "escaped_author" = $3, "updated_at" = $4 WHERE "books"."id" = $5  [["isbn", nil], ["author", "heyo"], ["escaped_author", "heyo"], ["updated_at", 2017-12-13 20:40:57 UTC], ["id", 5]]
   (0.6ms)  COMMIT
=> true
>> Book.select(:id, :author, :isbn).first
  Book Load (0.4ms)  SELECT  "books"."id", "books"."author", "books"."isbn" FROM "books" ORDER BY "books"."id" ASC LIMIT $1  [["LIMIT", 1]]
=> #<Book id: 5, isbn: nil, author: "heyo">