Mysql Frequency within date range - mysql

Question

I have a MySQL DB as such:
Date Customer_ID
How can I turn it into:
Customer_ID | Count_Visits_Past_Week | Count_Visits_Past_Month | Count_Visits_Past_90days | Count_Total
Note : Count_Total =sum of the other three counts
Thanks

Answer 1

The first step is to determine the demarcation points for the specified date ranges.
There's several questions to answer here: did you want to compare just the DATE ('yyyy-mm-dd') and disregard any time component?
By "past week", does that mean within the last seven days, or does it mean so far since the previous Sunday, or does it mean the last last full week, from Sunday through Saturday.
For "past month", does that mean the previous whole month, from the first through the end of the month? Or does it mean that if the query is run on the 20th of the month, we want dates since the 20th of the previous month up until today? Or yesterday?
Once we know the points in time that begin and end each specified period, relative to today's date, we can build expressions that evaluate to those dates.
For example, "past week" could be represented as the most recent seven day period:
DATE(NOW())-INTERVAL 1 WEEK -thru- DATE(NOW())
And "past month" can be represented as the same "day of month" (e.g. 17th) of the immediately preceding month up until today:
DATE(NOW())-INTERVAL 1 MONTH -thru- DATE(NOW())
That's really the first step, to determine the begin and end dates of each specified period.
Once we have that, we can move on to building a query that gets a "count" of rows with a date column that falls within each period.
The "trick" is to use conditional tests in expressions in the SELECT list of the query. We'll use those conditional tests to return a 1 if the row is to be included in the "count", and return 0 or NULL if the row should be excluded.
I prefer to use the SUM() aggregate function to get the "count". But it's also possible to use COUNT() aggregate. (If we use COUNT(), we need to use an expression that returns NULL when the row is to be excluded. I prefer to return a 1 or 0; I think it makes debugging easier.
Here's an outline of what a "count" query would look like.
SELECT t.Customer_Id
, SUM(IF( <some_condition> ,1,0) AS Count_something
, SUM(IF( <other_condition> ,1,0) AS Count_something_else
FROM mytable t
GROUP BY t.Customer_Id
When <some_condition> is true, we return a 1, otherwise we return 0.
To test the conditional expressions, it's often easiest to avoid doing the aggregation, and just return the individual rows:
That way, we can see which individual rows are going to be included in each "count".
For example:
SELECT t.Customer_ID
, t.date
, IF(t.date BETWEEN DATE(NOW())-INTERVAL 1 WEEK AND DATE(NOW()),1,0)
AS visit_past_week
, IF(t.date BETWEEN DATE(NOW())-INTERVAL 1 MONTH AND DATE(NOW()),1,0)
AS visit_past_month
FROM mytable t
ORDER BY t.date, t.Customer_Id
That query doesn't return the "count", it just returns the results of the expressions, which can be useful in testing. And of course we want to test the expressions that return the beginning and ending date of each period:
SELECT DATE(NOW()) - INTERVAL 1 WEEK AS past_week_begin
, DATE(NOW()) AS past_week_end
With this approach, the same row can be included in multiple "counts" with one query and one pass through the table.
Note that the expressions inside the SUM() aggregate in the query below are taking advantage of a convenient shorthand, an expression evaluated as a boolean will return 1 if TRUE, 0 if false, or a NULL.
To use the COUNT aggregate, we need to insure that the expression being aggregated returns a non-NULL when the row is to be "counted", and a NULL when the row is to be excluded from the count. So we use the convenient NULLIF function to return NULL if the value returned by the expression is a zero.
SELECT t.Customer_ID
, COUNT(NULLIF( t.date BETWEEN DATE(NOW())-INTERVAL 1 WEEK AND DATE(NOW()),0))
AS Count_Visits_Past_Week
, COUNT(NULLIF( t.date BETWEEN DATE(NOW())-INTERVAL 1 MONTH AND DATE(NOW()),0))
AS Count_Visits_Past_Month
, COUNT(NULLIF( t.date BETWEEN DATE(NOW())-INTERVAL 90 DAY AND DATE(NOW()),0))
AS Count_Visits_Past_90days
, COUNT(NULLIF( t.date BETWEEN DATE(NOW())-INTERVAL 1 WEEK AND DATE(NOW()),0))
+ COUNT(NULLIF( t.date BETWEEN DATE(NOW())-INTERVAL 1 MONTH AND DATE(NOW()),0))
+ COUNT(NULLIF( t.date BETWEEN DATE(NOW())-INTERVAL 90 DAY AND DATE(NOW()),0))
AS Count_Total
FROM mytable t
GROUP BY t.Customer_Id
NOTE: NULLIF(a,b) is a convenient shorthand for IF a IS NULL THEN return b ELSE return a
Returning the Count_Total is a bit odd, since it's got the potential to "count" the same row multiple times... but the value it returns should match the total of the individual counts.

Answer 2

I think this will give you what you want.
select customer_id,
sum(case when splitter = 'week' then num_visits else 0 end) as visits_this_week,
sum(case when splitter = 'month' then num_visits else 0 end) as visits_this_month,
sum(case when splitter = '90days' then num_visits else 0 end) as visits_last_90days,
sum(num_visits) as total
from (select customer_id, 'week' as splitter, count(*) as num_visits
from tbl
where extract(week from date) = extract(week from sysdate())
and extract(year from date) = extract(year from sysdate())
group by customer_id
union all
select customer_id, 'month' as splitter, count(*) as num_visits
from tbl
where extract(month from date) = extract(month from sysdate())
and extract(year from date) = extract(year from sysdate())
group by customer_id
union all
select customer_id, '90days' as splitter, count(*) as num_visits
from tbl
where date between date_sub(sysdate(), interval 90 day) and
sysdate()) x
group by customer_id
sql fiddle example: http://sqlfiddle.com/#!2/a762c/12/0