SELECT
1 AS Deptnumber
, Dept
FROM tbl_students
WHERE Dept IN ('A', 'B', 'C')
UNION
SELECT
2 AS DeptNumber
, Dept
FROM tbl_students
WHERE Dept IN ('D', 'E')
UNION
SELECT
3 AS Deptnumber
, Dept
FROM tbl_students
WHERE Dept IN ('F')
And then loop through the result set and elaborate the data according to the value of Deptnumber.
This is a great solution for combining queries to produce a single result, and very elegant! I will definitely be using this with frequency.
Here’s a question, though: suppose the number of sub-divisions of the query is indefinite, e.g. when the table contains a column that groups the rows based on a foreign key or some such. In this circumstance, the data to divide the results already exists in the table, but it can change as table data changes.
Is there a way to do a query like this dynamically, to do UNION / SELECT in a loop based on values in an existing column?
SELECT
SUM( IF( CAST(gamedata.Data AS UNSIGNED) >= 60 AND CAST(gamedata.Data AS UNSIGNED) <= 87,1,0) ) AS '60-87',
SUM( IF( CAST(gamedata.Data AS UNSIGNED) >= 88 AND CAST(gamedata.Data AS UNSIGNED) <= 115,1,0) ) AS '88-115',
SUM( IF( CAST(gamedata.Data AS UNSIGNED) >= 116 AND CAST(gamedata.Data AS UNSIGNED) <= 143,1,0) ) AS '116-143',
SUM( IF( CAST(gamedata.Data AS UNSIGNED) >= 144 AND CAST(gamedata.Data AS UNSIGNED) <= 171,1,0) ) AS '144-171',
SUM( IF( CAST(gamedata.Data AS UNSIGNED) >= 172 AND CAST(gamedata.Data AS UNSIGNED) <= 199,1,0) ) AS '172-199',
SUM( IF( CAST(gamedata.Data AS UNSIGNED) >= 200 AND CAST(gamedata.Data AS UNSIGNED) <= 227,1,0) ) AS '200-227',
SUM( IF( CAST(gamedata.Data AS UNSIGNED) >= 228 AND CAST(gamedata.Data AS UNSIGNED) <= 255,1,0) ) AS '228-255',
SUM( IF( CAST(gamedata.Data AS UNSIGNED) >= 256 AND CAST(gamedata.Data AS UNSIGNED) <= 283,1,0) ) AS '256-283',
SUM( IF( CAST(gamedata.Data AS UNSIGNED) >= 284 AND CAST(gamedata.Data AS UNSIGNED) <= 311,1,0) ) AS '284-311',
SUM( IF( CAST(gamedata.Data AS UNSIGNED) >= 312 AND CAST(gamedata.Data AS UNSIGNED) <= 339,1,0) ) AS '312-339'
FROM ...
that’s just brute force plain old SQL, even cruder than SQL Server’s PIVOT syntax
you have to hardcode for every column that you want
The first article was to solve a specific problem that author had; the second link gives a more detailed walkthrough of how to achieve cross-tabulation. I will still need to tinker with it to see if it can return data other than math calculations, because I would like to output VARCHAR fields that are a sorted list of categories and their subcategories. But it’s my understanding that SELECT CONCAT / SUM / IF will generate the SQL code necessary for the pivot table.