CODEWITHSUNDEEP
mysqlsql
Paul
Paul

Reputation: 45

MySQL sales data group by monthly average

I have a sales table with the following columns:

mysql> select * from sales;
+-------------+--------+------------+
| customer_id | amount | date       |
+-------------+--------+------------+
|           1 |     12 | 2015-01-01 |
|           1 |      1 | 2015-01-02 |
|           1 |    663 | 2015-02-12 |
|           2 |     22 | 2015-01-03 |
|           2 |     21 | 2015-02-12 |
|           2 |     11 | 2015-02-12 |
|           2 |      9 | 2015-04-12 |
+-------------+--------+------------+

And I can get near to what I want using this query:

SELECT
  customer_id,
  sum(if(month(date) = 1, amount, 0))  AS Jan,
  sum(if(month(date) = 2, amount, 0))  AS Feb,
  sum(if(month(date) = 3, amount, 0))  AS Mar,
  sum(if(month(date) = 4, amount, 0))  AS Apr,
  sum(if(month(date) = 5, amount, 0))  AS May,
  sum(if(month(date) = 6, amount, 0))  AS Jun,
  sum(if(month(date) = 7, amount, 0))  AS Jul,
  sum(if(month(date) = 8, amount, 0))  AS Aug,
  sum(if(month(date) = 9, amount, 0))  AS Sep,
  sum(if(month(date) = 10, amount, 0)) AS Oct,
  sum(if(month(date) = 11, amount, 0)) AS Nov,
  sum(if(month(date) = 12, amount, 0)) AS `Dec`
FROM sales
GROUP BY customer_id;

The output format required:

+-------------+------+------+------+------+------+------+------+------+------+------+------+------+
| customer_id | Jan  | Feb  | Mar  | Apr  | May  | Jun  | Jul  | Aug  | Sep  | Oct  | Nov  | Dec  |
+-------------+------+------+------+------+------+------+------+------+------+------+------+------+
|           1 |   13 |  663 |    0 |    0 |    0 |    0 |    0 |    0 |    0 |    0 |    0 |    0 |
|           2 |   22 |   32 |    0 |    9 |    0 |    0 |    0 |    0 |    0 |    0 |    0 |    0 |
+-------------+------+------+------+------+------+------+------+------+------+------+------+------+

However I'd like the average per month, when I change sum to avg, I dont get the average.

SELECT
  customer_id,
  avg(if(month(date) = 1, amount, 0))  AS Jan,
  avg(if(month(date) = 2, amount, 0))  AS Feb,
  avg(if(month(date) = 3, amount, 0))  AS Mar,
  avg(if(month(date) = 4, amount, 0))  AS Apr,
  avg(if(month(date) = 5, amount, 0))  AS May,
  avg(if(month(date) = 6, amount, 0))  AS Jun,
  avg(if(month(date) = 7, amount, 0))  AS Jul,
  avg(if(month(date) = 8, amount, 0))  AS Aug,
  avg(if(month(date) = 9, amount, 0))  AS Sep,
  avg(if(month(date) = 10, amount, 0)) AS Oct,
  avg(if(month(date) = 11, amount, 0)) AS Nov,
  avg(if(month(date) = 12, amount, 0)) AS `Dec`
FROM sales
GROUP BY customer_id;

Output (which isnt avg per month):

+-------------+--------+----------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+
| customer_id | Jan    | Feb      | Mar    | Apr    | May    | Jun    | Jul    | Aug    | Sep    | Oct    | Nov    | Dec    |
+-------------+--------+----------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+
|           1 | 4.3333 | 221.0000 | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 0.0000 |
|           2 | 5.5000 |   8.0000 | 0.0000 | 2.2500 | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 0.0000 |
+-------------+--------+----------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+

I'm going a bit mad trying to figure out whats happening, any one offer some advice? Thanks

CREATE TABLE `sales` (
  `customer_id` int(11) NOT NULL,
  `amount` int(11) DEFAULT NULL,
  `date` date DEFAULT NULL
) 

INSERT INTO `sales` VALUES (1,12,'2015-01-01'),(1,1,'2015-01-02'),(1,663,'2015-02-12'),(2,22,'2015-01-03'),(2,21,'2015-02-12'),(2,11,'2015-02-12'),(2,9,'2015-04-12');

Upvotes: 1

Views: 1691

Answers (4)

Deep
Deep

Reputation: 3202

A quick workaround is :

    SELECT 
  customer_id,
  MAX(if(`month` = 1, amount, 0))  AS Jan,
  MAX(if(`month` = 2, amount, 0))  AS Feb,
  MAX(if(`month` = 3, amount, 0))  AS Mar,
  MAX(if(`month` = 4, amount, 0))  AS Apr,
  MAX(if(`month` = 5, amount, 0))  AS May,
  MAX(if(`month` = 6, amount, 0))  AS Jun,
  MAX(if(`month` = 7, amount, 0))  AS Jul,
  MAX(if(`month` = 8, amount, 0))  AS Aug,
  MAX(if(`month` = 9, amount, 0))  AS Sep,
  MAX(if(`month` = 10, amount, 0)) AS Oct,
  MAX(if(`month` = 11, amount, 0)) AS Nov,
  MAX(if(`month` = 12, amount, 0)) AS `Dec`
FROM
(
  SELECT
    customer_id,
    (month(date)) `month`,
    AVG(amount) amount
  FROM sales
  GROUP BY customer_id,(month(date))
) AS T
GROUP BY customer_id;

SQLFiddle

Upvotes: 0

Sunil Patidar
Sunil Patidar

Reputation: 64

SELECT 
customer_id, 
SUM(Jan) AS Jun,
SUM(Feb) AS Feb,
SUM(Mar) AS Mar,
SUM(Apr) AS Apr,
SUM(May) AS May,
SUM(Jun) AS Jun,
SUM(Jul) AS Jul,
SUM(Aug) AS Aug,
SUM(Sep) AS Sep,
SUM(Oct) AS Oct,
SUM(Nov) AS Nov,
SUM(`Dec`) AS `Dec`
FROM (
SELECT
    customer_id,
    avg(if(month(date) = 1, amount, 0))  AS Jan,
    avg(if(month(date) = 2, amount, 0))  AS Feb,
    avg(if(month(date) = 3, amount, 0))  AS Mar,
    avg(if(month(date) = 4, amount, 0))  AS Apr,
    avg(if(month(date) = 5, amount, 0))  AS May,
    avg(if(month(date) = 6, amount, 0))  AS Jun,
    avg(if(month(date) = 7, amount, 0))  AS Jul,
    avg(if(month(date) = 8, amount, 0))  AS Aug,
    avg(if(month(date) = 9, amount, 0))  AS Sep,
    avg(if(month(date) = 10, amount, 0)) AS Oct,
    avg(if(month(date) = 11, amount, 0)) AS Nov,
    avg(if(month(date) = 12, amount, 0)) AS `Dec`
  FROM sales
  GROUP BY customer_id, month(date)
) AS a GROUP BY customer_id

Upvotes: 0

Gordon Linoff
Gordon Linoff

Reputation: 1270573

The problem are the 0s. The do not affect the sum(), but they do affect the average. You can change them to NULL:

SELECT customer_id,
       avg(if(month(date) = 1, amount, NULL))  AS Jan,
       avg(if(month(date) = 2, amount, NULL))  AS Feb,
       avg(if(month(date) = 3, amount, NULL))  AS Mar,
       avg(if(month(date) = 4, amount, NULL))  AS Apr,
       avg(if(month(date) = 5, amount, NULL))  AS May,
       avg(if(month(date) = 6, amount, NULL))  AS Jun,
       avg(if(month(date) = 7, amount, NULL))  AS Jul,
       avg(if(month(date) = 8, amount, NULL))  AS Aug,
       avg(if(month(date) = 9, amount, NULL))  AS Sep,
       avg(if(month(date) = 10, amount, NULL)) AS Oct,
       avg(if(month(date) = 11, amount, NULL)) AS Nov,
       avg(if(month(date) = 12, amount, NULL)) AS `Dec`
FROM sales
GROUP BY customer_id;

As a note: I prefer case because it is ANSI standard, so I would write this as:

       avg(case when month(date) = 1 then amount end) as Jan,

Upvotes: 2

user3426496
user3426496

Reputation: 125

Try something like this:

SELECT
    customer_id,
  if(month(hlp_tab2.date) = 1, hlp_tab2.amount, 0)  AS Jan,
  if(month(hlp_tab2.date) = 2, hlp_tab2.amount, 0)  AS Feb,
  if(month(hlp_tab2.date) = 3, hlp_tab2.amount, 0)  AS Mar,
  if(month(hlp_tab2.date) = 4, hlp_tab2.amount, 0)  AS Apr,
  if(month(hlp_tab2.date) = 5, hlp_tab2.amount, 0)  AS May,
  if(month(hlp_tab2.date) = 6, hlp_tab2.amount, 0)  AS Jun,
  if(month(hlp_tab2.date) = 7, hlp_tab2.amount, 0)  AS Jul,
  if(month(hlp_tab2.date) = 8, hlp_tab2.amount, 0)  AS Aug,
  if(month(hlp_tab2.date) = 9, hlp_tab2.amount, 0)  AS Sep,
  if(month(hlp_tab2.date) = 10, hlp_tab2.amount, 0) AS Oct,
  if(month(hlp_tab2.date) = 11, hlp_tab2.amount, 0) AS Nov,
  if(month(hlp_tab2.date) = 12, hlp_tab2.amount, 0) AS `Dec`
FROM (
    SELECT
        hlp_tab.customer_id,
        avg(hlp_tab.amount) 'amount',
        hlp_tab.date
    FROM (
        SELECT
          customer_id,
          amount,
          month(date) 'date'
        FROM sales
    ) hlp_tab
    group by
        hlp_tab.customer_id,
        hlp_tab.date
) hlp_tab2

Upvotes: 0

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