SQL query to return a grouped result as a single row

Question

If I have a jobs table like:

|id|created_at  |status    |
----------------------------
|1 |01-01-2015  |error     |
|2 |01-01-2015  |complete  |
|3 |01-01-2015           


        

Answer 1

The following should work in any RDBMS:

SELECT created_at, count(status) AS total,
       sum(case when status = 'error' then 1 end) as errors,
       sum(case when status = 'complete' then 1 end) as completed,
       sum(case when status = 'on hold' then 1 end) as on_hold
FROM jobs 
GROUP BY created_at;

The query uses conditional aggregation so as to pivot grouped data. It assumes that status values are known before-hand. If you have additional cases of status values, just add the corresponding sum(case ... expression.

Demo here