ClickHouse窗口函数在数据分析及开发中应用十分广泛。

具体可在官网查看，这里列举部分常用函数进行示例学习。

clickhouse官网-窗口函数 (opens new window)

• clickhouse 默认不允许使用窗口函数，可以在SQL末尾加：settings allow_experimental_window_functions = 1

SELECT 
    t1
  , row_number() OVER (ORDER BY t1 ) AS s1
  , rank()       OVER (ORDER BY t1 ) AS s2
  , dense_rank() OVER (ORDER BY t1 ) AS s3
from 
(
    select arrayJoin([1,2,3,2,4]) as t1
)
settings allow_experimental_window_functions = 1;

--    ┌─t1─┬─s1─┬─s2─┬─s3─┐
--    │  1 │  1 │  1 │  1 │
--    │  2 │  2 │  2 │  2 │
--    │  2 │  3 │  2 │  2 │
--    │  3 │  4 │  4 │  3 │
--    │  4 │  5 │  5 │  4 │
--    └────┴────┴────┴────┘