public class BetweenOperatorNode extends SqlNode implements OperatorNode {
  public void initialize() throws SemanticException {
    final Node fixture = getFixtureOperand();
    if ( fixture == null ) {
      throw new SemanticException( "fixture operand of a between operator was null" );
    }
    final Node low = getLowOperand();
    if ( low == null ) {
      throw new SemanticException( "low operand of a between operator was null" );
    }
    final Node high = getHighOperand();
    if ( high == null ) {
      throw new SemanticException( "high operand of a between operator was null" );
    }
    check( fixture, low, high );
    check( low, high, fixture );
    check( high, fixture, low );