Selecting COUNT(*) with DISTINCT

Question

In SQL Server 2005 I have a table cm_production that lists all the code that's been put into production. The table has a ticket_number, program_type, program_name and push_number along with some other columns.

GOAL: Count all the DISTINCT program names by program type and push number.

What I have so far is:

DECLARE @push_number INT;
SET @push_number = [HERE_ADD_NUMBER];

SELECT DISTINCT COUNT(*) AS Count, program_type AS [Type] 
FROM cm_production 
WHERE push_number=@push_number 
GROUP BY program_type

This gets me partway there, but it's counting all the program names, not the distinct ones (which I don't expect it to do in that query). I guess I just can't wrap my head around how to tell it to count only the distinct program names without selecting them. Or something.

Answer 1

Count all the DISTINCT program names by program type and push number

SELECT COUNT(DISTINCT program_name) AS Count,
  program_type AS [Type] 
FROM cm_production 
WHERE push_number=@push_number 
GROUP BY program_type

DISTINCT COUNT(*) will return a row for each unique count. What you want is COUNT(DISTINCT <expression>): evaluates expression for each row in a group and returns the number of unique, non-null values.

Answer 2

I needed to get the number of occurrences of each distinct value. The column contained Region info. The simple SQL query I ended up with was:

SELECT Region, count(*)
FROM item
WHERE Region is not null
GROUP BY Region

Which would give me a list like, say:

Region, count
Denmark, 4
Sweden, 1
USA, 10

Answer 3

You have to create a derived table for the distinct columns and then query the count from that table:

SELECT COUNT(*) 
FROM (SELECT DISTINCT column1,column2
      FROM  tablename  
      WHERE condition ) as dt

Here dt is a derived table.

Answer 4

SELECT COUNT(DISTINCT program_name) AS Count, program_type AS [Type] 
FROM cm_production 
WHERE push_number=@push_number 
GROUP BY program_type

Answer 5

try this:

SELECT
    COUNT(program_name) AS [Count],program_type AS [Type]
    FROM (SELECT DISTINCT program_name,program_type
              FROM cm_production 
              WHERE push_number=@push_number
         ) dt
    GROUP BY program_type

Answer 6

This is a good example where you want to get count of Pincode which stored in the last of address field

SELECT DISTINCT
    RIGHT (address, 6),
    count(*) AS count
FROM
    datafile
WHERE
    address IS NOT NULL
GROUP BY
    RIGHT (address, 6)