Question

I need to make a complex query, and I need help. Below is an example of what do i have:

id   |   Date   |  Validity

48   | 6-1-2009 |  notFound   
47   | 6-1-2009 |  valid   
46   | 6-1-2009 |  valid    
45   | 3-1-2009 |  invalid   
44   | 3-1-2009 |  invalid   
42   | 4-1-2009 |  notFound 
41   | 4-1-2009 |  notFound
48   | 4-1-2009 |  valid 

[Here come the SQL.]

And the query result would look like:

   Date   |  valid   |  invalid   |    notFound

 3-1-2009 |   0      |     2      |       0
 4-1-2009 |   1      |     2      |       2
 6-1-2009 |   3      |     2      |       3

Can i do this only in SQLite? Can someone help me? I’m working in Python.

I need this to generate a line graph out of it. The example would be: line chart!

Answer 1

Your Date column cannot be properly sorted because it does not begin with the most significant field, the year.

Assuming that you change the date to have a proper yyyy-mm-dd format, you could use something like this:

SELECT A.Date,
       (SELECT COUNT(*) FROM MyTable AS B
        WHERE B.Date <= A.Date
          AND B.Validity = 'valid') AS valid,
       (SELECT COUNT(*) FROM MyTable AS B
        WHERE B.Date <= A.Date
          AND B.Validity = 'invalid') AS invalid,
       (SELECT COUNT(*) FROM MyTable AS B
        WHERE B.Date <= A.Date
          AND B.Validity = 'notFound') AS notFound
FROM (SELECT DISTINCT Date FROM MyTable
      ORDER BY Date) AS A