} else if (theType == null) {
return LiteralExpression.newConstant(null, theType, isDeterministic);
} else if (theType == PDataType.TIMESTAMP || theType == PDataType.UNSIGNED_TIMESTAMP) {
return new TimestampSubtractExpression(children);
} else if (theType.isCoercibleTo(PDataType.DATE)) {
return new DateSubtractExpression(children);
} else {
throw TypeMismatchException.newException(theType, node.toString());
}
}
});