How to get dynamic columns for a query - mysql

Question

I want to create a SQL query which should generate columns according to date range.
For example, if my input parameters for date range in 2013-01-01 and 2013-06-07. Then the query should dynamically create seven month columns between these above two dates. The output should look like this:
data column1 column2 Jan-13 feb-13 mar-13 apr-13 may-13 jun-13 jul-13
I have tried couple of times but not reached to the desired result.
Please share your ideas on this. How should I proceed?
SELECT a.* ,
(SELECT SUM(fid1.TOTAL_AMOUNT) FROM
fact_invoice_details fid1
WHERE DATE_FORMAT(dd.thedate, '%b %y') LIKE '%Jan%' ) AS 'Jan',
(SELECT SUM(fid1.TOTAL_AMOUNT) FROM
fact_invoice_details fid1
where DATE_FORMAT(dd.thedate, '%b %y') LIKE '%Feb%' ) AS 'Feb'
FROM
(
SELECT DISTINCT gl.ACCOUNT_NUMBER,
gl.NAME AS 'GL_Account_Name',
di.account_id 'ACCOUNT_ID',
dpp.company_name 'ACCOUNT_NAME',
dd3.thedate AS 'INVOICE_DATE',
di.OCCURRED_ON_DATE_ID,
di.INVOICE_ID ,
di.INVOICE_NUMBER ,
fid.INVOICE_ITEM_ID,
dpro.sku,
dpro.PRODUCT_NAME,
dci.ISO,
fid.TOTAL_AMOUNT
-- DATE_FORMAT(dd3.thedate, '%b %y') as mon
FROM dim_gl_account gl
/* Some tables also having here */
WHERE dte.TENANT_ID = 155
AND dd3.thedate BETWEEN CAST('2013-01-01' AS DATE) AND CAST('2013-03-01' AS DATE) ) a
as i can not paste the whole code .

Answer 1

What you are attempting to do is pivot the data from rows into columns. Unfortunately MySQL does not have this capability, however, we can use an aggregate function with a CASE statement to get a similar result.
SELECT
cid,
SUM(CASE WHEN YEAR(duedate) = 2013 AND MONTH(duedate) = 1 THEN total ELSE 0 END) AS JAN_13,
SUM(CASE WHEN YEAR(duedate) = 2013 AND MONTH(duedate) = 2 THEN total ELSE 0 END) AS FEB_13,
SUM(CASE WHEN YEAR(duedate) = 2013 AND MONTH(duedate) = 3 THEN total ELSE 0 END) AS MAR_13,
SUM(CASE WHEN YEAR(duedate) = 2013 AND MONTH(duedate) = 4 THEN total ELSE 0 END) AS ARR_13,
SUM(CASE WHEN YEAR(duedate) = 2013 AND MONTH(duedate) = 5 THEN total ELSE 0 END) AS MAY_13,
SUM(CASE WHEN YEAR(duedate) = 2013 AND MONTH(duedate) = 6 THEN total ELSE 0 END) AS JUN_13,
SUM(CASE WHEN YEAR(duedate) = 2013 AND MONTH(duedate) = 7 THEN total ELSE 0 END) AS JUL_13
FROM invoices
GROUP BY cid
DEMO
Basically we supplied a CASE line for each month/year that we want to get the SUM for. You could include a line for each month/year and add back the date ranges to your WHERE clause but this would still create columns for all the months with zero values as seen here.
A better way to do this dynamically would be to use a prepared statement. This way we can supply our date range in the WHERE clause and let SQL do the heavy lifting.
SET #sql = NULL;
SELECT
GROUP_CONCAT(DISTINCT
CONCAT(
'SUM(CASE WHEN MonthYear = ''',
MonthYear,
''' THEN total ELSE 0 END) AS ',
MonthYear
)
) INTO #sql
FROM (
SELECT
cid,
DATE_FORMAT(duedate, '%b_%y') MonthYear,
total
FROM invoices
WHERE duedate BETWEEN CAST('2013-01-01' AS DATE) AND CAST('2013-07-31' AS DATE)
ORDER BY duedate
) src;
SET #sql = CONCAT("SELECT cid, ", #sql, "
FROM (
SELECT
cid,
DATE_FORMAT(duedate, '%b_%y') MonthYear,
total
FROM invoices
WHERE duedate BETWEEN CAST('2013-01-01' AS DATE) AND CAST('2013-07-31' AS DATE)
ORDER BY duedate
) src
GROUP BY cid");
PREPARE stmt FROM #sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
DEMO
My examples are obviously much simpler then the snippet you provided but you should be able to incorporate the logic back into your queries. Depending on how you will be making calls you might also consider using a stored procedure as well. Finally, here is a link to an article discussing pivot like functions for MySQL.
Dynamic pivot tables (transform rows to columns)