Question

EDIT: OK, think I need to be clearer – I’d like the result to show all the ‘names’ that appear in the table acme, against the counts (if any) from the results table. Hope that makes sense?

Having a huge issue and my brain isn’t working as it should.

All I want to do is, in a single statement via a join, count the number of rows for a common field.

   SELECT name, COUNT(name) as Count FROM acme
   SELECT name, COUNT(name) as Total FROM results

I’m sure it should be something like this…

   SELECT acme.name, COUNT(acme.name) As Count, 
          COUNT(results.name) as Total 
   FROM acme 
   LEFT JOIN results ON acme.name = results.name 
   GROUP BY name 
   ORDERY BY name

But it doesn’t bring back the correct counts.

Thoughts, where am I going wrong…this, I know, will be very very obvious.

H.

Answer 1

From your feedback, this will get what you want. You need to FIRST get unique names / counts from the “ACME” file first… THEN join that to the results table for count of records from that, otherwise, you would end up with a Cartesian result of counts. If ACME had Name “X” 5 times and Results had “X” 20 times, your total would be 100. The query below will actually result with a single row showing “X”, 5, 20 which is what it appears you are looking for.. (for however many names exist in ACME).

I’ve changed to a LEFT join in case there are names in the ACME table that DO NOT exist in the RESULTS table, it won’t drop them from your final answer

select
      JustACME.Name,
      JustACME.NameCount,
      COALESCE( COUNT( * ), 0 ) as CountFromResultsTable
   from
      ( select a.Name
               count(*) as NameCount
           from
              acme a
           group by
              a.Name ) JustACME

      LEFT JOIN results r
         on JustACME.Name = r.Name
   group by
      JustACME.Name