Junior SQL Developer

Question

I was recently laid off and have been on a few technical interviews and clam up on some questions. Any advice on SQL technical interviews ?

Answer 1

You should know main SQL functions. How they works and how you can combine them. How to JOIN tables. Diff between UNION and UNION ALL. Subqueries. What is isnull/ifnull/nullif/coalesce/nvl and why NULL is better then 0 in some cases. All that you HAVE TO know.