技術標籤：clickhouse

資料

a,2017-02-05,200
a,2017-02-06,300
a,2017-02-07,200
a,2017-02-08,400
a,2017-02-10,600
b,2017-02-05,200
b,2017-02-06,300
b,2017-02-08,200
b,2017-02-09,400
b,2017-02-10,600
c,2017-01-31,200
c,2017-02-01,300
c,2017-02-02,200
c,2017-02-03,400
c,2017-02-10,600
a,2017-03-01,200
a,2017-03-02,300
a,2017-03-03,200
a,2017-03-04,400
a,2017-03-05,600

建表，匯入資料

create table shop(
name String,
 

ctime Date,
cost Float64
)
engine=MergeTree
primary key (name,ctime)
order by (name,ctime);

cat shop.csv | clickhouse-client -q 'insert into shop FORMAT CSV';

select 
name,groupArray(ctime) arr,
arrayEnumerate(arr)  arr_index
from 
shop
group by name
┌─name─┬─arr─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┬─arr_index──────────────┐
│ b    │ [
 
'2017-02-05','2017-02-06','2017-02-08','2017-02-09','2017-02-10']                                                                  │ [1,2,3,4,5]            │
│ c    │ ['2017-01-31','2017-02-01','2017-02-02','2017-02-03','2017-02-10']                                                                  │ [1,2,3,4,5]            │
│ a    │ [
 
'2017-02-05','2017-02-06','2017-02-07','2017-02-08','2017-02-10','2017-03-01','2017-03-02','2017-03-03','2017-03-04','2017-03-05'] │ [1,2,3,4,5,6,7,8,9,10] │
└──────┴─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴────────────────────────┘

select
name,ct,idx,
subtractDays(ct,idx) diff  --日期減去天數
from
	(select 
	name,groupArray(ctime) arr,
	arrayEnumerate(arr)  arr_index
	from 
	shop
	group by name)
array join arr as ct,
arr_index as idx  --在登入日期後面生成連續的數字
┌─name─┬─────────ct─┬─idx─┬───────diff─┐
│ b    │ 2017-02-05 │   1 │ 2017-02-04 │
│ b    │ 2017-02-06 │   2 │ 2017-02-04 │
│ b    │ 2017-02-08 │   3 │ 2017-02-05 │
│ b    │ 2017-02-09 │   4 │ 2017-02-05 │
│ b    │ 2017-02-10 │   5 │ 2017-02-05 │
│ c    │ 2017-01-31 │   1 │ 2017-01-30 │
│ c    │ 2017-02-01 │   2 │ 2017-01-30 │
│ c    │ 2017-02-02 │   3 │ 2017-01-30 │
│ c    │ 2017-02-03 │   4 │ 2017-01-30 │
│ c    │ 2017-02-10 │   5 │ 2017-02-05 │
│ a    │ 2017-02-05 │   1 │ 2017-02-04 │
│ a    │ 2017-02-06 │   2 │ 2017-02-04 │
│ a    │ 2017-02-07 │   3 │ 2017-02-04 │
│ a    │ 2017-02-08 │   4 │ 2017-02-04 │
│ a    │ 2017-02-10 │   5 │ 2017-02-05 │
│ a    │ 2017-03-01 │   6 │ 2017-02-23 │
│ a    │ 2017-03-02 │   7 │ 2017-02-23 │
│ a    │ 2017-03-03 │   8 │ 2017-02-23 │
│ a    │ 2017-03-04 │   9 │ 2017-02-23 │
│ a    │ 2017-03-05 │  10 │ 2017-02-23 │
└──────┴────────────┴─────┴────────────┘

select
name,count(1) days
from
	(select
	name,ct,idx,
	subtractDays(ct,idx) diff
	from
		(select 
		name,groupArray(ctime) arr,
		arrayEnumerate(arr)  arr_index
		from 
		shop
		group by name)
	array join arr as ct,
	arr_index as idx)
group by name,diff
order by name,days desc
limit 1 by name;

┌─name─┬─days─┐
│ a    │    5 │
│ b    │    3 │
│ c    │    4 │
└──────┴──────┘