}
		for _, arg := range e.SFunc.ArgsList {
			result.combine(arg.analyze(s))
		}
		return result

	case sqlFnNullIf:
		if len(e.SFunc.ArgsList) != 2 {
			return qProp{err: fmt.Errorf("%s needs exactly 2 arguments", string(funcName))}
		}
		for _, arg := range e.SFunc.ArgsList {
			result.combine(arg.analyze(s))
		}
		return result