SQL(BigQuery) 中 2020 年 5 月 1 日至 2021 年 4 月 30 日之间一周中每一天的计数答案

【问题标题】：Count of each day of the week between May 01, 2020 and April 30, 2021 in SQL(BigQuery)SQL(BigQuery) 中 2020 年 5 月 1 日至 2021 年 4 月 30 日之间一周中每一天的计数
【发布时间】：2021-09-01 22:36:33
【问题描述】：

我需要在 SQL(BigQuery) 中计算 2020 年 5 月 1 日至 2021 年 4 月 30 日期间一周中每一天的总出现次数（# of Sundays、# of Mondays 等）。

我有以下相关领域可以使用：

Field	Type
started_at_cst	DATETIME
ended_at_cst	DATETIME
Day_of_Week	STRING

期间的开始日期将是从 started_at_cst 开始的最早日期，结束日期将是从ended_at_cst 开始的最晚日期。

【问题讨论】：

您希望结果是什么样的？数据是否以多行形式出现？

标签： sql google-bigquery

【解决方案1】：

首先，您应该创建您要创建报告的期间的每日记录。为此，您可以创建一个表作为“日历表”。

CREATE TABLE dbo.CalendarTable
    (
    Date datetime NOT NULL,
    DayWeekNumber nvarchar(50) NULL
    )  ON [PRIMARY]
GO
ALTER TABLE dbo.CalendarTable ADD CONSTRAINT
    PK_CalendarTable PRIMARY KEY CLUSTERED 
    (
    Date
    ) WITH( STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
Go

之后你应该像这样填写日历表：


Truncate Table CalendarTable
Declare @FromDate as datetime , @ToDate as datetime, @counter as int , @DateRecord as int,
@Date as Datetime

Set @FromDate = '2020-03-21'
Set @ToDate = '2021-03-21'
Set @Counter = 1

Set @DateRecord = dateDiff(D,@FromDate, @ToDate)

While (@Counter <=@DateRecord)
BEGIN
Insert Into CalendarTable (Date,DayWeekNumber)
    Select DateAdd(d,@Counter,@FromDate),DATEPART(dw,DateAdd(d,@Counter,@FromDate))
Set @Counter += 1

END

最后将它与您的出现表连接起来

Select Date,(Select Count(*) From occurrencesTable Where started_at_cst>= CalendarTable.Date
and ended_at_cst<= CalendarTable.Date ) as NumberOfOccurence from CalendarTable

【讨论】：

【解决方案2】：

借助GENERATE_ARRAY 功能，您可以得到您想要的：

WITH dow_generated AS (
    # Step 2. Extract the day of the week for each generated date
    SELECT
        FORMAT_DATE("%A",dates) AS day_of_week
    FROM (
            # Step 1. Generate an array of dates from minimum of started_at_cst to maximumn of ended_at_cst
            SELECT 
                GENERATE_DATE_ARRAY(MIN(started_at_cst), MAX(ended_at_cst)) as dates
            FROM `your_table`) dates_generated, unnest(dates_generated.dates) dates)

# Step 3. Count the different days of the week
SELECT day_of_week, COUNT(day_of_week) AS day_count
FROM dow_generated
GROUP BY day_of_week

你应该得到一个像这样的表：

【讨论】：

【解决方案3】：

大概，您希望得到您指定格式的结果。如果是这样，这应该做你想要的：

WITH t AS (
       select datetime('2020-05-01') as started_at_cst, datetime('2021-05-30') as ended_at_cst
)
SELECT FORMAT_DATE('%A', dte) AS day_of_week, COUNT(*) AS day_count
FROM (SELECT MIN(started_at_cst) as min_started_at_cst, MAX(ended_at_cst) as max_ended_at_cst
      FROM t
     ) t CROSS JOIN
     UNNEST(GENERATE_DATE_ARRAY(DATE(min_started_at_cst), DATE(max_ended_at_cst), INTERVAL 1 day)) dte
GROUP BY day_of_week
ORDER BY MIN(dte)

【讨论】：

【解决方案4】：

考虑下面

select format_date('%A', day) day_of_the_week, count(1) days_count 
from `project.dataset.table`,
unnest(generate_date_array(date(started_at_cst), date(ended_at_cst))) day
where day between '2020-05-01' and '2021-04-30'
group by day_of_the_week

如果您希望输出按工作日排序 - 请在下方添加 order by

order by case day_of_the_week
  when 'Monday' then 1
  when 'Tuesday' then 2
  when 'Wednesday' then 3
  when 'Thursday' then 4
  when 'Friday' then 5
  when 'Saturday' then 6
  when 'Sunday' then 7
end

最后 - 如果上面的顺序对你来说太罗嗦 - 使用下面的版本

select day_of_the_week, count(1) days_count , pos
from (
  select format_date('%A', day) day_of_the_week, format_date('%u', day) pos
  from `project.dataset.table`,
  unnest(generate_date_array(date(started_at_cst), date(ended_at_cst))) day
  where day between '2020-05-01' and '2021-04-30'
)  
group by day_of_the_week, pos
order by pos

【讨论】：