calculate sales per day in MySQL - php

Question

I have a simple table which holds the date and the total sales made for a certain group:
date | totalsales
=======================
2014-05-01 | 3000
2014-05-02 | 3100
2014-05-03 | 3500
2014-05-04 | 3650
I like to calculate some things like:
sales per day
average sales
growth in %
Result should look like (calculate by hand so maybe wrong :) )
date | sales | average | growth
=======================================
2014-05-01 | 0 | 0 | 0
2014-05-02 | 100 | 50 | 100
2014-05-03 | 400 | 166.66 | 400
2014-05-04 | 150 | 162.5 | 37.5
Is this even possible in a sql statement or should I calculate with PHP or another server software?

Answer 1

Assuming each date gets its own unique row, you could do it by joining back to your original table like so:
SELECT t1.Date, CASE WHEN t2.Date IS NULL THEN 0 ELSE (t1.totalsales - t2.totalsales)
END AS sales
FROM table t1
LEFT JOIN table t2 ON t2.Date = DATE_ADD(t1.Date, INTERVAL -1 DAY)
ORDER BY 1
This will give you at least your first column, and you should be able to figure out the math for the rest from there. It's important to use a left join with the CASE statement here because otherwise you won't get the lowest date in your table (your first row)
If each date does not get its own unique row, this is method is still viable, you just need to create your datasets in a subquery using GROUP BY and SUM on the date column.

Answer 2

Here is the full query with no subselect at each row : (Thanks to #nmarsh for writting the hardest part)
See SQL fiddle : http://sqlfiddle.com/#!2/be4654/34/0
SELECT
t1.Date,
CASE
WHEN t2.date IS NULL THEN 0 ELSE (t1.totalSales - t2.totalSales)
END AS sales,
CASE
WHEN t2.date IS NULL THEN 0 / (#curRow := #curRow + 1) ELSE ((#curSum := #curSum + (t1.totalSales - t2.totalSales)) / (#curRow := #curRow + 1))
END AS average,
CASE
WHEN t3.date IS NULL AND t2.date IS NULL THEN 0
WHEN t3.date IS NULL THEN (t1.totalSales - t2.totalSales)
WHEN t2.date IS NULL THEN 0 ELSE ((t1.totalSales - t2.totalSales) * 100) / (t2.totalSales - t3.totalSales)
END AS growth
FROM test t1
LEFT JOIN test t2 ON t2.date = DATE_ADD(t1.Date, INTERVAL -1 DAY)
LEFT JOIN test t3 ON t3.date = DATE_ADD(t2.Date, INTERVAL -1 DAY)
JOIN (SELECT #curRow := 0) r
JOIN (SELECT #curSum := 0) ct
ORDER BY 1;
Original table :
date | totalsales
=======================
2014-05-01 | 3000
2014-05-02 | 3100
2014-05-03 | 3500
2014-05-04 | 3650
OUTPUT
date | sales | average | growth
=======================================
2014-05-01 | 0 | 0 | 0
2014-05-02 | 100 | 50 | 100
2014-05-03 | 400 | 166.66 | 400
2014-05-04 | 150 | 162.5 | 37.5

Answer 3

You can use recursive statement. In each iteration, calculate the requested data for one day, and drop the first (oldest) day.
You can also do it with PHP, which seems better because you don't want to put too much load on the MySQL tables in case it does not saves you time/calculations.

Answer 4

Not too sure about the numbers, but if you are more specific about the results I can double check.
You can use ROW_NUMBER() to create 2 data sets and join them on ROW_NUMBER() and ROW_NUMBER()-1 to get an offset to current and previous values to calculate the growth. Sample :
DECLARE #Data TABLE (SalesDate DATETIME, totalSales INT)
INSERT INTO #Data (SalesDate , totalSales) VALUES ('2014-05-01' , 3000)
INSERT INTO #Data (SalesDate , totalSales) VALUES ('2014-05-02' , 3100)
INSERT INTO #Data (SalesDate , totalSales) VALUES ('2014-05-03' , 3500)
INSERT INTO #Data (SalesDate , totalSales) VALUES ('2014-05-04' , 3650)
SELECT
CurrentDt.SalesDate
,ISNULL(CurrentDt.totalSales - PreviousDt.totalSales ,0) AS Sales
,FirstDate.FirstDate
, NULLIF(CAST((CurrentDt.SalesDate - FirstDate.FirstDate) AS INT)+1,0) AS SellingDays
,(ISNULL(CurrentDt.totalSales - PreviousDt.totalSales ,0))
/ NULLIF(CAST((CurrentDt.SalesDate - FirstDate.FirstDate) AS INT)+1,0) AS AverageSales
FROM
(SELECT Min(SalesDate) AS FirstDate FROM #Data) AS FirstDate,
/*Base Sales Data*/
(
SELECT
ROW_NUMBER() OVER(ORDER BY SalesDate) AS RowNum
,SalesDate
,totalSales
FROM
#Data
) AS CurrentDt
/*Previous Value for Growth*/
LEFT JOIN
(
SELECT
ROW_NUMBER() OVER(ORDER BY SalesDate) AS RowNum
,SalesDate
,totalSales
FROM
#Data
) AS PreviousDt
ON CurrentDt.RowNum -1 = PreviousDt.RowNum
I have used MSSQL, but MySQL supports ROW_NUMBER OVER.

Answer 5

I hope this query help you
SELECT
sample.id,
sample.date AS oggi,
sample.value AS sales,
((SELECT SUM(sample.value) FROM sample WHERE sample.date <= oggi ) / (SELECT COUNT(sample.value) FROM sample WHERE sample.date <= oggi ) ) AS avarege,
sample.value / IF((SELECT sample.value FROM sample WHERE sample.date = (oggi - INTERVAL 1 DAY )) = 0,sample.value,(SELECT sample.value FROM sample WHERE sample.date = (oggi - INTERVAL 1 DAY ))) *100 AS 'growt-percent'
-- (SELECT SUM(sample.value) FROM sample WHERE sample.date <= oggi ) AS somma,
-- (SELECT count(sample.value) FROM sample WHERE sample.date <= oggi ) AS conta,
-- (SELECT sample.value FROM sample WHERE sample.date = (oggi - INTERVAL 1 DAY )) as valoreieri,
FROM sample
WHERE sample.date BETWEEN '2014-05-01 00:00:00' AND '2014-05-31 00:00:00'
table data is
id date value
1 2014-05-01 00:00:00 0
2 2014-05-02 00:00:00 100
3 2014-05-03 00:00:00 400
4 2014-05-04 00:00:00 150
5 2014-05-05 00:00:00 200
result is
id oggi sales avarege growt-percent
1 2014-05-01 00:00:00 0 0.0000 (NULL)
2 2014-05-02 00:00:00 100 50.0000 100.0000
3 2014-05-03 00:00:00 400 166.6667 400.0000
4 2014-05-04 00:00:00 150 162.5000 37.5000
5 2014-05-05 00:00:00 200 170.0000 133.3333
note that i use datetime field not only date
if you have question about query ask
sorry for my bad english
edit
the last 3 rows are commented because i used it only for test