Question

I’ve currently got a table as follows,

Column      Type
time        datetime             
ticket      int(20)              
agentid     int(20)              
ExitStatus  varchar(50)      
Queue       varchar(50)

I want to write a query which will break this down by week, providing a column with a count for each ExitStatus. So far I have this,

SELECT ExitStatus,COUNT(ExitStatus) AS ExitStatusCount, DAY(time) AS TimePeriod 
FROM `table` 
GROUP BY TimePeriod, ExitStatus

Output:

ExitStatus ExitStatusCount TimePeriod
NoAgentID                1          4 
Success                  3          4
NoAgentID                1          5
Success                  5          5

I want to change this so it returns results in this format:

week | COUNT(NoAgentID) | COUNT(Success) | 

Ideally, I’d like the columns to be dynamic as other ExitStatus values may be possible.

This information will be formatted and presented to end user in a table on a page. Can this be done in SQL or should I reformat it in PHP?

Answer 1

There is no “general” solution to your problem (called cross tabulation) that can be achieved with a single query. There are four possible solutions:

• Hardcode all possible ExitStatus‘es in your query and keep it updated as you see the need for more and more of them. For example:

SELECT
    Day(Time) AS TimePeriod,
    SUM(IF(ExitStatus = 'NoAgentID', 1, 0)) AS NoAgentID,
    SUM(IF(ExitStatus = 'Success', 1, 0)) AS Success
    -- #TODO: Add others here when/if needed
FROM table
WHERE ...
GROUP BY TimePeriod

• Do a first query to get all possible ExitStatus‘es and then create your final query from your high-level programming language based on those results.

• Use a special module for cross tabulation on your high-level programming language. For Perl, you have the SQLCrossTab module but I couldn’t find one for PHP

• Add another layer to your application by using OLAP (multi-dimensional views of your data) like Pentaho and then querying that layer instead of your original data

You can read a lot more about these solutions and an overall discussion of the subject