How to get multiple counts with one SQL query?

Question

I am wondering how to write this query.

I know this actual syntax is bogus, but it will help you understand what I am wanting. I need it in this format, because it is part of a much bigger query.

SELECT distributor_id, 
COUNT(*) AS TOTAL, 
COUNT(*) WHERE level = 'exec', 
COUNT(*) WHERE level = 'personal'

I need this all returned in one query.

Also, it need to be in one row, so the following won't work:

'SELECT distributor_id, COUNT(*)
GROUP BY distributor_id'

Answer 1

For mysql this can be shorten to

select distributor_id,
    count(*) total,
    sum(level = 'exec') ExecCount,
    sum(level = 'personal') PersonalCount
from yourtable
group by distributor_id

Answer 2

You can use a CASE statement with an aggregate function. This is basically the same thing as a PIVOT function in some RDBMS:

select distributor_id,
    count(*) total,
    sum(case when level = 'exec' then 1 else 0 end) ExecCount,
    sum(case when level = 'personal' then 1 else 0 end) PersonalCount
from yourtable
group by distributor_id

Answer 3

Well, if you must have it all in one query, you could do a union:

SELECT distributor_id, COUNT() FROM ... UNION
SELECT COUNT() AS EXEC_COUNT FROM ... WHERE level = 'exec' UNION
SELECT COUNT(*) AS PERSONAL_COUNT FROM ... WHERE level = 'personal';

Or, if you can do after processing:

SELECT distributor_id, COUNT(*) FROM ... GROUP BY level;

You will get the count for each level and need to sum them all up to get the total.

Answer 4

Based on Bluefeet's accepted response with an added nuance using OVER ()

select distributor_id,
    count(*) total,
    sum(case when level = 'exec' then 1 else 0 end) OVER() ExecCount,
    sum(case when level = 'personal' then 1 else 0 end) OVER () PersonalCount
from yourtable
group by distributor_id

Using OVER() with nothing in the () will give you the total count for the whole dataset.

Answer 5

I do something like this where I just give each table a string name to identify it in column A, and a count for column. Then I union them all so they stack. The result is pretty in my opinion - not sure how efficient it is compared to other options but it got me what I needed.

select 'table1', count (*) from table1
union select 'table2', count (*) from table2
union select 'table3', count (*) from table3
union select 'table4', count (*) from table4
union select 'table5', count (*) from table5
union select 'table6', count (*) from table6
union select 'table7', count (*) from table7;

Result:

-------------------
| String  | Count |
-------------------
| table1  | 123   |
| table2  | 234   |
| table3  | 345   |
| table4  | 456   |
| table5  | 567   |
-------------------

Answer 6

One way which works for sure

SELECT a.distributor_id,
    (SELECT COUNT(*) FROM myTable WHERE level='personal' and distributor_id = a.distributor_id) as PersonalCount,
    (SELECT COUNT(*) FROM myTable WHERE level='exec' and distributor_id = a.distributor_id) as ExecCount,
    (SELECT COUNT(*) FROM myTable WHERE distributor_id = a.distributor_id) as TotalCount
FROM (SELECT DISTINCT distributor_id FROM myTable) a ;

EDIT:
See @KevinBalmforth's break down of performance for why you likely don't want to use this method and instead should opt for @bluefeet's answer. I'm leaving this so people can understand their options.