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012. null test

VBScript

JScript

Perl

PHP

Python

Ruby

PowerShell

Scala

F#

C

C++

C++Builder

VC++

C#

Java

Objective-C

D

VB

VB.NET

Delphi

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x = nil

Ada

x = null

PL/SQL

x is NULL
x = NULL is always false

T-SQL