case types.UntypedString,
			types.String:
			return m.t&argString != 0

		case types.UnsafePointer:
			return m.t&(argPointer|argInt) != 0

		case types.UntypedRune:
			return m.t&(argInt|argRune) != 0

		case types.UntypedNil:
			return false

		case types.Invalid:
			return true // Probably a type check problem.
		}
		panic("unreachable")
	}

	return false
}

			e.aggregate.runningCount++
			return nil
		}

		val, err = e.Count.ExprArg.evalNode(r, tableAlias)
		if err != nil {
			return err
		}
	} else {
		// Evaluate the (only) argument
		val, err = e.SFunc.ArgsList[0].evalNode(r, tableAlias)
		if err != nil {
			return err
		}
	}

	if val.IsNull() {
		// E.g. the column or field does not exist in the
		// record - in all such cases the aggregation is not
		// updated.