MYSQL计数 - 如果为null则返回0

Question

Here's my query:

select COUNT(*) as total, COUNT(distinct user) as unique 
FROM table 
WHERE uristem in ('/example/', '/example/', '/example/', '/example/') 
      and time > DATE_SUB(NOW(), INTERVAL 24 HOUR)' 
group by uristem;

Should look like this

100 50
25  50
0   0
100 35

But if there is no count, it looks like this (missing)

100 50
40  50
100 35

How can I fill in 0's instead?

Answer 1

If you don't have a table with the uri stems in then something ugly like

Select
  u.uristem,
  count(t.uristem),
  count(distinct t.user) as unique
From (
    Select '/example1/' As uristem
    Union All Select '/example2/'
    Union All Select '/example3/'
    Union All Select '/example4/'
  ) u
    Left Outer Join
  table t
    On u.uristem = t.uristem And
    t.time > Date_Sub(Now(), Interval 24 Hour)
 Group By
   u.uristem

Should do it

Answer 2

Try this (untested):

select COUNT(t.uristem) as total
, COUNT(distinct t.user) as unique 
FROM 
    (
        select uristem, user
        from table
        where time > DATE_SUB(NOW(), INTERVAL 24 HOUR) 
    ) t
right outer join 
(
    select '/example/' x
    union select '/example/'
    union select '/example/'
    union select '/example/'
) y
on t.uristem = y.x
group by y.x;