mysql queries for aggregation

I have an order table that contains dates and amounts for each order, this table is big and contains more that 1000000 records and growing.

We need to create a set of queries to calculate certain milestones, is there a way in mysql to figure out on which date we reached an aggregate milestone开发者_如何学Go of x amount.

For e.g we crossed 1 m sales on '2011-01-01'

Currently we scan the entire table then use the logic in PHP to figure out the date, but it would be great if this could be done in mysql without reading so many records at 1 time.

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There maybe elegant approaches, but what you can do is maintain a row in another table which contains, current_sales and date it occurred. Every time you have a sale, increment the value, and store sales date. If the expected milestones(1 Million, 2 Million etc) are known in advance, you can store them away when they occur(in same or different table)

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i think using gunner's logic with trigger will be a good option as it reduce your efforts to maintain the row and after that you can send mail notification through trigger to know the milestone status