Mar 6, 2012 · The reasoning is that a null means "unknown", so the result of any comparison to a null is also "unknown". So you'll get no hit on rows by coding where my_column = null. SQL …

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 …

Sep 21, 2021 · The only difference (besides the syntax) is, that the compiler guarantees that no user-overloaded operator is called when using is not null instead of != null (or is null instead of …

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, 2013 · The operators for Nullable<T> are so-called "lifted" operators]; the c# compiler takes the operators available for T and applies a set of pre-defined rules; for example, with +, …

The title of this bug says "check for undefined or null", but the question itself checks for undeclared or null.

Jul 20, 2010 · How do I refer to the null object in Python?

89 NOT IN returns 0 records when compared against an unknown value Since NULL is an unknown, a NOT IN query containing a NULL or NULL s in the list of possible values will …

In C, there appear to be differences between various values of zero -- NULL, NUL and 0. I know that the ASCII character '0' evaluates to 48 or 0x30. The NULL pointer is usually defined as: …

Jun 28, 2011 · This comes in handy if you want a null item to appear in the JSON so the consumer doesn't have to do any special handling. If, for example, the consumer needs to …