Question

I’m having a question that can be explained using a simple fictive table.

Table “Drinks” has just three fields:

• Id (1..N) – Primary key
• Date (‘2012-09-19’…) – Each date can occur very often
• Hot (1 for yes, and 0 for false).

I would like to produce a list like this:

    Date         Total    Hot    Cold
    2012-09-19   14       6      8
    2012-09-10   21       18     3

Etc.

The field “Cold” is as you might expect calculated as (Total – Hot).

What I’ve got so far is:

    SELECT Date, count(*) AS Total FROM Drinks GROUP BY Date;

This gives me the desired table, but of course without the columns “Hot” and “Cold”.

Is there a way to modify my query so I can produce this table in one go? I can of course built the table in phases using PHP code, but that is probably not the elegant way nor the fastest.

I’m happy to watch and learn… 🙂

Answer 1

SELECT Date,
    count(*) AS Total,
    SUM(Hot = 1) Hot,
    SUM(Hot = 0) Cold
FROM Drinks
GROUP BY Date;