如何从一个表中选择特定年份不存在的所有记录？

Question

the table looks like this

num  Year
 1 | 2014
 2 | 2014
 3 | 2014
 2 | 2015
 4 | 2015
 5 | 2015
 6 | 2015

I would like my query to return

 4 | 2014
 5 | 2014
 6 | 2014
 1 | 2015
 3 | 2015

from 1 to 6, the number that is not used in particular year.

Answer 1

Generate the all the combinations and then take out the ones that exist:

select n.num, y.year
from (select distinct num from t) n cross join
     (select distinct year from t) y left join
     t
     on t.num = n.num and t.year = y.year
where t.num is null;

Note that year is a bad name for a column in SQL Server because it is the name of a function and a keyword (think datepart() ).