isnull Function

Checks if an argument value contains a null value. When the argument value is null, the function returns true. Otherwise, it returns false.

Category: Information and Conversion
Returned data type: Integer
Note: The returned value is a Boolean value.

Syntax

<boolean>isnull(<argvalue>)

Required Argument

argvalue

string, date, integer, real, Boolean

Details

The isnull function takes the following argument types: string, date integer, real, Boolean.

Examples

Example 1

// Expression

if State <> "NC" OR isnull(State)

   return true

else

   return false

Example 2

integer x

string y

string error_message1

string error_message2

 

y="Hello"

 

if(isnull(x) )

   error_message1 = "Integer x is null"

else

   error_message1= "Integer x is not null"

 

if( isnull(y) )

   error_message2 =" String y value is null"

else

   error_message2 =" String y value is not null"