c# - What does null! statement mean? - Stack Overflow
Feb 16, 2019 · It can be used on a type to control Nullability, it is then called the "Null Forgiving Operator". Basically, null! applies the ! operator to the value null. This overrides the nullability …
SQL is null and = null - Stack Overflow
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 …
What is the purpose of null? - Stack Overflow
Feb 25, 2009 · Null: The Billion Dollar Mistake. Tony Hoare: I call it my billion-dollar mistake. It was the invention of the null reference in 1965. At that time, I was designing the first …
javascript - Why is null an object and what's the difference …
Apr 29, 2009 · In order to be able to query this difference, JavaScript has null and undefined: While null is - just like in other languages an object, undefined cannot be an object because …
sql - Not equal <> != operator on NULL - Stack Overflow
Apr 14, 2011 · 135 NULL has no value, and so cannot be compared using the scalar value operators. In other words, no value can ever be equal to (or not equal to) NULL because NULL …
Why does NULL = NULL evaluate to false in SQL server
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 …
What is null in Java? - Stack Overflow
Apr 25, 2010 · The null reference can always be cast to any reference type. In practice, the programmer can ignore the null type and just pretend that null is merely a special literal that …
What's the difference between " = null" and " IS NULL"?
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 …
Java null check why use == instead of .equals () - Stack Overflow
In Java I am told that when doing a null check one should use == instead of .equals(). What are the reasons for this?
How can I check for an undefined or null variable in JavaScript?
The one benefit I can see is that it does not require knowing that == null and != null treat a declared variable with value undefined as equal to null. IMHO, that isn't reason enough to use …