Why do I need “OR NULL” in MySQL when counting rows with a condition

Question

There is a question about MySQL\'s COUNT() aggregate function that keeps popping into my head time to time. I would like to get some explanation to why it is working the way

Answer 1

I would suggest that you will find the more standard syntax moves better between different database engines and will always give the correct result.

 select count(*)
 from test
 where value = 4

Is the syntax you used a Mysql variant?