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  • c# - What does null! statement mean? - Stack Overflow
    null! is used to assign null to non-nullable variables, which is a way of promising that the variable won't be null when it is actually used I'd use null! in a Visual Studio extension, where properties are initialized by MEF via reflection:
  • Whats the difference between = null and IS NULL?
    Now IS NULL is a little trickier and is the preferred method for evaluating the condition of a variable being NULL When you use the “IS NULL” clause, it checks both the address of the variable and the data within the variable as being unknown So if I for example do:
  • sql - Not equal lt; gt; != operator on NULL - Stack Overflow
    Which is why you can only use IS NULL IS NOT NULL as predicates for such situations This behavior is not specific to SQL Server All standards-compliant SQL dialects work the same way Note: To compare if your value is not null, you use IS NOT NULL, while to compare with not null value, you use <> 'YOUR_VALUE' I can't say if my value equals
  • javascript - Why is null an object and whats the difference between . . .
    The surprise expressed by JavaScript developers at typeof null === "object" is the result of an impedance mismatch (or abstraction leak) between a weakly-typed language (JavaScript) that has both null and undefined, and another, strongly-typed language (Java) that only has null, and in which null is strictly defined to refer to a reference type
  • Java null check why use == instead of . equals() - Stack Overflow
    @RogerWang - Good question! The answer is that null isn't an object, it's an object reference (a blank one) It's the only object reference we can write literally in code So Object a = null; Object b = null; means that a == b is true, because both variables contain the same object reference (the single universal blank one) –
  • 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)
  • JavaScript checking for null vs. undefined and difference between . . .
    typeof null returning "object" makes sense The only other value that would make sense would be "null", since it definitely should return something different from typeof undefined null represents a null object reference, which, at the very least, means the variable holding it is meant for some type of 'object'
  • What is null in Java? - Stack Overflow
    The null reference is the only possible value of an expression of null type 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 can be of any reference type
  • language agnostic - What is the purpose of null? - Stack Overflow
    Also, the null character in a C-style variable length string is used to mark the end of the string The use of null in these ways, especially for pointer values, has become so popular that the metaphor has been imported into other systems, even when the "null" sentinel value is implemented entirely differently and has no relation to the number 0
  • Why does NULL = NULL evaluate to false in SQL server
    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 to DBMS vendor) The expression "x IS NOT NULL" is not equal to "NOT(x IS NULL)", as is the case in 2VL





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