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Siebel Developer's Reference > Operators and Expressions > Operators > NULL OperatorThe NULL operator in an SQL statement represents a value that is not known or is not applicable. Siebel CRM evaluates an expression that includes a NULL operator differently than it evaluates other operators. NULL is not a value. A comparison function does not operate correctly if a NULL operator exists in the comparison. For instance, if NULL = NULL is not TRUE. Note the following:
IS NULL OperatorThe IS NULL operator is a unary operator. A unary operation is an operation that includes only one operand. If you use the IS NULL operator, and if the operand for this operator evaluates to: You cannot use the = (equal) operator to determine if a value is NULL because a NULL operand does not contain a value. IfNull FunctionThe IfNull function contains two arguments and returns the value of the first or second argument depending on if the first argument is NULL. IfNull (a,b) returns one of the following values: Siebel CRM sets the return type of the IfNull function to the type of the first argument that it contains, even if this first argument is NULL. Siebel CRM converts the second argument to the type of the first argument before it returns the value of the IfNull function. Flag Fields and NULLA flag field is a type of field that Siebel CRM can evaluate to a Boolean value, such as True or False, or Y or N. You can use a flag field to turn functionality on or off. A flag field is typically but not always a calculated field. If you configure Siebel CRM to query a flag field, then you must use caution. The <> (not equal to) and NOT IN comparison operators cannot evaluate a field that contains a null value. Siebel CRM sets the default value of a flag field to null, so a workflow condition of <>'Y' does not work. To avoid this situation, you can do one of the following: |
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