Dec 4, 2009 · The expression "NULL = NULL" evaluates to NULL, but is actually invalid in SQL; yet ORDER BY treats NULLs as equal (whatever they precede or follow "regular" values is left …

May 1, 2010 · Understanding the difference between “IS NULL” and “= NULL” When a variable is created in SQL with the declare statement it is created with no data and stored in the variable …

And then == null does a perfect job, because it covers exactly those 2 values. (i.e. == null is equivalent to === null && === undefined) In exceptional cases you do want a clear distinction …

Sep 6, 2017 · Comparing NULL with anything yields a NULL. NULL is part of trinary logic: TRUE, FALSE, and NULL. -- These are all NULL. select NULL > -1, NULL < -1, NULL = NULL, NULL …

So if you don't need to support the difference between empty and null/absent string you may also consider the empty parameter as null. If instead you want to recreate point 4. of JSON …

Aug 13, 2009 · I have a table create table us ( a number ); Now I have data like: a 1 2 3 4 null null null 8 9 Now I need a single query to count null and not null values in column a

Mar 8, 2012 · I know that in most programming scenarios, the preference is for empty collections to null collections when there are 0 elements. However, most languages that consume JSON …

I have some code and when it executes, it throws a NullReferenceException, saying: Object reference not set to an instance of an object. What does this mean, and what can I do to fix …

In other words, a null pointer is a pointer of any type pointing at a well-defined "nowhere". Any pointer can turn into a null pointer when it is assigned a null pointer constant. The standard …

If you try to access a member of a class instance using a null reference then you get a System.NullReferenceException. Which is the same as Object reference not set to an instance …