errFunctionNotImplemented = errors.New("Function is not yet implemented")
	errUnexpectedInvalidNode  = errors.New("Unexpected node value")
	errInvalidKeypath         = errors.New("A provided keypath is invalid")
)

// qProp contains analysis info about an SQL term.
type qProp struct {
	isAggregation, isRowFunc bool

	err error
}

// `combine` combines a pair of `qProp`s, so that errors are