offset 行後にある行で評価された値を返します。
leadInFrame の動作は、標準 SQL の lead ウィンドウ関数とは異なります。
ClickHouse のウィンドウ関数 leadInFrame は、ウィンドウフレームに従って動作します。
lead と同じ動作にするには、ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING を使用してください。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])
x— カラム名。offset— 適用する OFFSET。(U)Int*。 (省略可。デフォルトは1) 。default— 計算対象の行がウィンドウフレームの境界を超えた場合に返す値。 (省略可。省略時はカラム型のデフォルト値) 。
- 順序付けられたフレーム内で、現在の行から
offset行後の行で評価された値。
leadInFrame 関数で物理学部門の連続する受賞者のリストを返します。
Query
CREATE OR REPLACE VIEW nobel_prize_laureates
AS SELECT *
FROM file('nobel_laureates_data.csv');
Query
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
┌─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 │
└──────────────────┴──────┴──────────┴────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘