Distinct count using lookup table

Question

How can I get a distinct count of column values using a different table?
Let's say I want to get a distinct count of all "company_name" records in table "emp" that corespond (match) with "lookup" table, "state" category.
What I want is to find counts for all companies that have a value of "california" in the "state" column of the "lookup" Table. I want the output to look like:
Sears 17
Pennys 22
Marshalls 6
Macys 9
I want the result to show me the company names dynamically as I don't know what they are, just that they are part of the "state" group in the lookup Table. Does this make sense?
M

Answer 1

Mark,
In the future you might consider creating test cases for us to work with. Something similar to the following where sample data is created for each table as the union all of multiple select statementsselect 'INIT_ASSESS' lookup_type
     , 1 lookup_value
     , 'Initial Assessment' lookup_value_desc
  from dual union all
select 'JOB_REF', 2, 'Job Reference' from dual union all
select 'SPEC_STA', 3, 'SPEC STA' from dual;
select 'INIT_ASSESS' rfs_category
     , 1 val
  from dual union all
select 'JOB_REF', 1 from dual union all
select 'JOB_REF', 1 from dual union all
select 'SPEC_STA', null from dual;Then we can either take your select statements and make them the source of a CTAS (create table as) statementcreate table lookup as
select 'INIT_ASSESS' lookup_type
     , 1 lookup_value
     , 'Initial Assessment' lookup_value_desc
  from dual union all
select 'JOB_REF', 2, 'Job Reference' from dual union all
select 'SPEC_STA', 3, 'SPEC STA' from dual;, or include them as subfactored queries by using the with statement:with lookup as (
select 'INIT_ASSESS' lookup_type
     , 1 lookup_value
     , 'Initial Assessment' lookup_value_desc
  from dual union all
select 'JOB_REF', 2, 'Job Reference' from dual union all
select 'SPEC_STA', 3, 'SPEC STA' from dual
), RFS as (
select 'INIT_ASSESS' rfs_category
     , 1 val
  from dual union all
select 'JOB_REF', 1 from dual union all
select 'JOB_REF', 1 from dual union all
select 'SPEC_STA', null from dual
select lookup_value_desc, count_all, count_val, dist_val
  from lookup
  join (select rfs_category
             , count(*) count_all
             , count(val) count_val
             , count(distinct val) dist_val
          from RFS group by rfs_category)
    on rfs_category = lookup_type;Edited by: Sentinel on Nov 17, 2008 3:38 PM