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Null - a variable that has no value

var Null : Variant; Description The Null variable has an undefined value. Null does not mean a zero number or empty string - it is undefined. Any expression using a null variable will yield a null result. Null is particularly useful when handling SQL table data - providing a one for one correspondence with the SQL NULL value. Notes The Null variable is the Null Variant. Calculations using nulls yield the EVariantError. Related commands Pointer Defines a general use Pointer to any memory based data Variant A variable type that can hold changing data types Example code : Using Null to represent the result of a bad divide var Answer : Variant; begin Answer := Divide(4,2); // Show the result of this division if Answer = Null then ShowMessage('4 / 2 = Invalid') else ShowMessage('4 / 2 = '+IntToStr(Answer)); Answer := Divide(4,0); // Show the result of this division if Answer = Null then ShowMessage('4 / 0 = Invalid') else ShowMessage('4 / 0 = '+IntToStr(Answer)); end; function TForm1.Divide(Dividend, Divisor: Integer) : Variant; begin // Try to divide the Dividend by the Divisor try Result := Dividend div Divisor; except Result := Null ; // Assign Null if the division threw an error end; end; Show full unit code 4 / 2 = 2 4 / 0 = Invalid