Calculate a running total in MySQL

Question

I have this MySQL query:

SELECT DAYOFYEAR(`date`)  AS d, COUNT(*) 
FROM  `orders` 
WHERE  `hasPaid` > 0
GROUP  BY d
ORDER  BY d

Which re

Answer 1

It is possible to calculate a running balance using a temporary table in MySQL. The following query should work:

CREATE TEMPORARY table orders_temp1 (SELECT id, DAYOFYEAR(`date`)  AS d, COUNT(*) as total FROM  `orders` WHERE  `hasPaid` > 0 GROUP BY d ORDER  BY d);
CREATE TEMPORARY table orders_temp2 (SELECT * FROM orders_temp1);
SELECT d, total, (SELECT SUM(t2.total) FROM orders_temp2 t2 WHERE t2.id<=t1.id) as running_total FROM orders_temp1 t1;

A temporary table is used for organizing the query. Note that a temporary table only exists for the duration of the connection to the MySQL server

The above query uses a sub query, which returns balance of all rows in the temporary table upto and including the current row. The balance is assigned to the current row in the actual table