Your requirements are a bit unclear but this may work for you

WITH CTE AS(

SELECT book,position,

ROW_NUMBER() OVER(PARTITION BY position ORDER BY book) AS rn

FROM mytable)

SELECT a.book, a.position

FROM CTE a

WHERE EXISTS(SELECT * FROM CTE b WHERE b.position = -a.position

AND b.rn = a.rn)

ORDER BY book;

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Deja View - The strange feeling that somewhere, sometime you've optimised this query before

How to get the best help on a forum

http://www.sqlservercentral.com/articles/Best+Practices/61537