need pivot table query

i have two table tbl_category

id category 
1   cat1 
2   cat2
3   cat3

and second table Tbl_book

id  cat_id  book_name
1    1      book1
2    1      book2
3    2      book4
4    1      book5

i need query for pivot table

look like

category  n1    n2    n3     n4    n5  
cat1     book1  book2 book5  NULL  NUll 
cat2     book4  NULL  NULL   NULL  NUll