return charlen(argVals[0])

	case sqlFnLower:
		return lowerCase(argVals[0])

	case sqlFnUpper:
		return upperCase(argVals[0])

	case sqlFnUTCNow:
		return handleUTCNow()

	case sqlFnToString, sqlFnToTimestamp:
		// TODO: implement
		fallthrough

	default:
		return nil, errNotImplemented
	}
}

func coalesce(args []*Value) (res *Value, err error) {