Question

Newbie here.

I’m using codeigniter and mysql
How can I dynamically (number of names may change) convert table from:

+------+-------+-------+
| date | name  | value |
+------+-------+-------+
| 06-01|   A   |  1    |
| 06-02|   A   |  2    |
| 06-02|   B   |  3    |
| 06-03|   C   |  4    |
+------+-------+-------+

To:

+------+---+---+---+
| date | A | B | C |
+------|---+---+---|
| 06-01| 1 |   |   |
| 06-02| 2 | 3 |   |   
| 06-03|   |   | 4 |
+------+---+---+---+

?

Thank you.

Answer 1

Something like this should work.

SELECT date,
       SUM(IF(name='A',value,0)) AS 'A',
       SUM(IF(name='B',value,0)) AS 'B',
       SUM(IF(name='C',value,0)) AS 'C'
FROM myTable
GROUP BY date
ORDER BY date

You need to know what your column names could be to add each of the SUMs manually into your SQL statement, but you could do this using PHP if it was likely to change a lot.

Likewise, replace value with 1 if you just wanted a count of how many times each name appeared, rather than the total of the values in name.