> ## Documentation Index
> Fetch the complete documentation index at: https://private-7c7dfe99-mintlify-8a08bda2.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

> Documentação da função de janela leadInFrame

# leadInFrame

Retorna um valor avaliado na linha que está a `offset` linhas após a linha atual dentro da janela ordenada.

<Warning>
  O comportamento de `leadInFrame` difere do da função de janela padrão SQL `lead`.
  A função de janela `leadInFrame` do ClickHouse respeita o frame da janela.
  Para obter um comportamento idêntico ao de `lead`, use `ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING`.
</Warning>

**Sintaxe**

```sql theme={null}
leadInFrame(x[, offset[, default]])
  OVER ([[PARTITION BY grouping_column] [ORDER BY sorting_column]
        [ROWS or RANGE expression_to_bound_rows_withing_the_group]] | [window_name])
FROM table_name
WINDOW window_name as ([[PARTITION BY grouping_column] [ORDER BY sorting_column])
```

Para mais detalhes sobre a sintaxe de funções de janela, consulte: [Funções de janela - Sintaxe](/pt-BR/reference/functions/window-functions#syntax).

**Parâmetros**

* `x` — Nome da coluna.
* `offset` — Deslocamento a ser aplicado. [(U)Int\*](/pt-BR/reference/data-types/int-uint). (Opcional — `1` por padrão).
* `default` — Valor a ser retornado se a linha calculada exceder os limites do frame da janela. (Opcional — valor padrão do tipo da coluna quando omitido).

**Valor retornado**

* valor avaliado na linha que está a `offset` linhas após a linha atual dentro do frame ordenado.

**Exemplo**

Este exemplo analisa [dados históricos](https://www.kaggle.com/datasets/sazidthe1/nobel-prize-data) de vencedores do Prêmio Nobel e usa a função `leadInFrame` para retornar uma lista de vencedores sucessivos na categoria de física.

```sql title="Query" theme={null}
CREATE OR REPLACE VIEW nobel_prize_laureates
AS SELECT *
FROM file('nobel_laureates_data.csv');
```

```sql title="Query" theme={null}
SELECT
    fullName,
    leadInFrame(year, 1, year) OVER (PARTITION BY category ORDER BY year ASC
      ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
    ) AS year,
    category,
    motivation
FROM nobel_prize_laureates
WHERE category = 'physics'
ORDER BY year DESC
LIMIT 9
```

```response title="Response" theme={null}
   ┌─fullName─────────┬─year─┬─category─┬─motivation─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
1. │ Anne L Huillier  │ 2023 │ physics  │ for experimental methods that generate attosecond pulses of light for the study of electron dynamics in matter                     │
2. │ Pierre Agostini  │ 2023 │ physics  │ for experimental methods that generate attosecond pulses of light for the study of electron dynamics in matter                     │
3. │ Ferenc Krausz    │ 2023 │ physics  │ for experimental methods that generate attosecond pulses of light for the study of electron dynamics in matter                     │
4. │ Alain Aspect     │ 2022 │ physics  │ for experiments with entangled photons establishing the violation of Bell inequalities and  pioneering quantum information science │
5. │ Anton Zeilinger  │ 2022 │ physics  │ for experiments with entangled photons establishing the violation of Bell inequalities and  pioneering quantum information science │
6. │ John Clauser     │ 2022 │ physics  │ for experiments with entangled photons establishing the violation of Bell inequalities and  pioneering quantum information science │
7. │ Giorgio Parisi   │ 2021 │ physics  │ for the discovery of the interplay of disorder and fluctuations in physical systems from atomic to planetary scales                │
8. │ Klaus Hasselmann │ 2021 │ physics  │ for the physical modelling of Earths climate quantifying variability and reliably predicting global warming                        │
9. │ Syukuro Manabe   │ 2021 │ physics  │ for the physical modelling of Earths climate quantifying variability and reliably predicting global warming                        │
   └──────────────────┴──────┴──────────┴────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
```