org.axiondb.functions
Class NullIfFunction
java.lang.Object
org.axiondb.BaseSelectable
org.axiondb.functions.BaseFunction
org.axiondb.functions.NullIfFunction
- All Implemented Interfaces:
- Serializable, Function, FunctionFactory, ConcreteFunction, ScalarFunction, Selectable
public class NullIfFunction
- extends BaseFunction
- implements ScalarFunction, FunctionFactory
The NULLIF function returns a null value if the arguments are equal, otherwise it
returns the value of the first argument.
The result of using NULLIF(e1,e2) is the same as using the expression
CASE WHEN e1=e2 THEN NULL ELSE e1 END
- Version:
- $Revision: 1.5 $ $Date: 2005/12/20 18:32:28 $
- See Also:
- Serialized Form
NullIfFunction
public NullIfFunction()
makeNewInstance
public ConcreteFunction makeNewInstance()
- Specified by:
makeNewInstance
in interface FunctionFactory
getDataType
public DataType getDataType()
AnyType
- Specified by:
getDataType
in interface Selectable
- Specified by:
getDataType
in class BaseFunction
evaluate
public Object evaluate(RowDecorator row)
throws AxionException
- Specified by:
evaluate
in interface ScalarFunction
- Specified by:
evaluate
in interface Selectable
- Throws:
AxionException
isValid
public boolean isValid()
- Specified by:
isValid
in interface ConcreteFunction
- Specified by:
isValid
in class BaseFunction