Sådan returneres 1 enkelt række data fra 2 forskellige tabeller med dynamisk indhold i sql

Hvis du tager et kig her:http://www.simple-talk.com/sql/t-sql-programming/concatenating-row-values-in-transact-sql/

der er flere teknikker, du kan gøre dette.

Tilpasning til din situation, her er en, der ser enkel ud:

    select batch_no, LEFT(booksauthors, len(booksauthors)-1) as Authors from 
(SELECT ba.Batch_no,

      ( SELECT cast(ba1.Author_no as varchar(10)) + ','

           FROM Book_Authors ba1

          WHERE ba1.Batch_no = ba.Batch_no

          ORDER BY Author_no

            FOR XML PATH('') ) AS BooksAuthors

      FROM Book_Authors ba

      GROUP BY Batch_no )A;