McKinsey SQL Interview Question | Easy Level 

Select q.*, case when n.npv is not null then n.npv else 0 end as npv from queries as q left join npv as n on q.id=n.id and q.year=n.year

Though I was able to solve this question but still this video is very helpful . Thanks a lot

Good Explanation

Nice explanation ,,

another approoach select q.id, q.year,COALESCE(n.npv,0) from npv as n right join queries as q on n.id=q.id and n.year=q.year;

Instead of IFNULL ,we can use NVL…