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- c# - What does null! statement mean? - Stack Overflow
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 of the value null to non-nullable, telling the compiler that null is a "non-null" type
- What is the difference between is not null and != null?
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 == null) From operator overloading: A user-defined type can overload a predefined C# operator That is, a type can provide the custom implementation of an operation in case one or both of the operands are of that
- sql - Not equal lt; gt; != operator on NULL - Stack Overflow
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 has no value Hence, SQL has special IS NULL and IS NOT NULL predicates for dealing with NULL
- SQL is null and = null - Stack Overflow
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 provides the special syntax for testing if a column is null, via is null and is not null, which is a special condition to test for a null (or not a null)
- What is the purpose of null? - Stack Overflow
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 comprehensive type system for references in an object oriented language (ALGOL W) My goal was to ensure that all use of references should be absolutely safe, with checking performed automatically by the compiler But I
- When should I use ?? (nullish coalescing) vs || (logical OR)?
In short, when you care that let a variable assigned from a possible null undefined source, and you wish to provide a default value to the variable, use the nullish coalescing operator ??
- Whats the difference between = null and IS NULL?
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 table (vtable) inside SQLs memory space The vtable contains the name and memory address of the variable
- JavaScript checking for null vs. undefined and difference between . . .
How do I check a variable if it's null or undefined and what is the difference between the null and undefined? What is the difference between == and === (it's hard to search Google for "===" )?
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