How do a default value and a Nullable Column work together in one table? Two short scripts from an interview panel show exactly what SQL Server does.
Can We Have NULL Value in Primary Key? – Interview Question of the Week #075
Can we have a NULL value in primary key columns? No. The primary key has to uniquely identify each row, and NULL cannot do that. Here is why.
What is NOT NULL Constraint? – Interview Question of the Week #073
A client table full of NULL values was hurting query plans. Here is what a NOT NULL constraint is, how to add one and why it helped performance.
SQL SERVER – Interesting Observation of CONCAT_NULL_YIELDS_NULL and CONCAT
Have you ever worked with CONCAT_NULL_YIELDS_NULL earlier in your career? If yes, you will find this post very interesting for CONCAT.
SQL SERVER – SSMS Does NOT Print NULL Values
Here is a very interesting question asked on the blog by Karthik. I really liked the question and I would like to discuss this here about SSMS doe snot Print NULL values.
SQL SERVER – A Puzzle – Fun with NULL – Fix Error 8117
NULL is fun to ask about in interviews, since every answer I get is different. A short puzzle on NULL that raises Error 8117, and how to fix it.
SQL SERVER – Solution Part 2 – A Quick Puzzle on SQL JOIN and NULL – SQL Brain Teaser
Part 2 of the solution to my puzzle on SQL Join and NULL. Readers still email me answers every day, so here are more of the good ones they sent.