Question

Is there a way to combine these queries so that I get a distinct name, then the quantity for today, tomorrow, and the day after tomorrow

select name, SUM(qty) as qty_today, 0 as qty_tomororow, 0 as qty_om  
from order_item
where delivery_date = '2011-11-22'
group by name
union all
select name, qty as qty_today, SUM(qty) as qty_tomororow, 0 as qty_om  
from order_item
where delivery_date = '2011-11-23'
group by name
union all
select name, 0 as qty_today, 0 as qty_tomororow, SUM(qty) as qty_om  
from order_item
where delivery_date = '2011-11-24'
group by name

UPDATE
Given the table
name, qty, delivery_date
Chicago, 1, 2011-11-22
New York, 2, 2011-11-22
Chicago, 3, 2011-11-23

I would expect
Chicago, 1, 3, 0
New York, 1, 0, 0

Answer 1

If you are trying to combine all of them in one dataset you can try this,

SELECT name, 
       SUM(CASE WHEN delivery_date = '2011-11-22' THEN qty 
                ELSE 0 END) AS qty_today,
       SUM(CASE WHEN delivery_date = '2011-11-23' THEN qty 
                ELSE 0 END) AS qty_tomororow,
       SUM(CASE WHEN delivery_date = '2011-11-24' THEN qty 
                ELSE 0 END) AS qty_om
from order_item
where delivery_date between '2011-11-22' and '2011-11-24'
group by name

This would work in TSQL (MS SQL), hopefully it’s the same syntax in MySql