Columns to Rows queries - mysql

Question

I have a table that look like this:
Company Year Revenue Cost Profit
ABC 1 10 6 4
ABC 2 12 7 5
ABC 3 14 8 6
XYZ 1 25 18 7
XYZ 2 27 19 8
XYZ 3 29 20 9
I want it look like this:
Company Item 1 2 3
ABC Revenue 10 12 14
ABC Cost 6 7 8
ABC Profit 4 5 6
XYZ Revenue 25 27 29
XYZ Cost 18 19 20
XYZ Profit 7 8 9
A crosstab query only allows one value. I can do it using separate crosstab queries for Revenue, Cost And Profit and the combine using the Union function but there must be an easier way.
Any help would be really appreciated.
Max

Answer 1

Variation for you to try.
SELECT Company,
item,
SUBSTRING_INDEX(SUBSTRING_INDEX(item_details, ',', 1), ',', -1) AS `1`,
SUBSTRING_INDEX(SUBSTRING_INDEX(item_details, ',', 2), ',', -1) AS `2`,
SUBSTRING_INDEX(SUBSTRING_INDEX(item_details, ',', 3), ',', -1) AS `3`
FROM
(
SELECT Company, 'Revenue' AS item, GROUP_CONCAT(Revenue ORDER BY `Year`) AS item_details
FROM SomeTable
GROUP BY Company
UNION
SELECT Company, 'Cost' AS item, GROUP_CONCAT(Cost ORDER BY `Year`)
FROM SomeTable
GROUP BY Company
UNION
SELECT Company, 'Profit' AS item, GROUP_CONCAT(Profit ORDER BY `Year`)
FROM SomeTable
GROUP BY Company
) Sub1
ORDER BY Company, FIELD(Item, 'Revenue', 'Cost', 'Profit')
SQL fiddle for you:-
http://www.sqlfiddle.com/#!2/995a0/6

Answer 2

For reasons of scalability (and flexibility), problems like this are best left to the application level code (e.g. a simple PHP loop on a well-ordered result set) but, just for fun...
SELECT company
, item
, MAX(CASE WHEN year = 1 THEN value END) y1
, MAX(CASE WHEN year = 2 THEN value END) y2
, MAX(CASE WHEN year = 3 THEN value END) y3
FROM
( SELECT company, year, 'revenue' item, revenue value FROM my_table
UNION
SELECT company, year, 'cost',cost FROM my_table
UNION
SELECT company, year, 'profit',profit FROM my_table
) x
GROUP
BY company
, item
ORDER
BY company
, FIELD(item,'Revenue','Cost','Profit');

Answer 3

Try this:
SELECT Company, Item, Col1 AS 1, Col2 AS 2, Col3 AS 3
FROM (SELECT a.Company, 'Revenue' AS Item, MAX(IF(a.Year = 1, a.Revenue, 0)) AS Col1,
MAX(IF(a.Year = 2, a.Revenue, 0)) AS Col2, MAX(IF(a.Year = 3, a.Revenue, 0)) AS Col3
FROM tableA a
GROUP BY a.Company
UNION
SELECT a.Company, 'Cost' AS Item, MAX(IF(a.Year = 1, a.Cost, 0)) AS Col1,
MAX(IF(a.Year = 2, a.Cost, 0)) AS Col2, MAX(IF(a.Year = 3, a.Cost, 0)) AS Col3
FROM tableA a
GROUP BY a.Company
UNION
SELECT a.Company, 'Profit' AS Item, MAX(IF(a.Year = 1, a.Profit, 0)) AS Col1,
MAX(IF(a.Year = 2, a.Profit, 0)) AS Col2, MAX(IF(a.Year = 3, a.Profit, 0)) AS Col3
FROM tableA a
GROUP BY a.Company
) AS A
ORDER BY Company, FIELD(Item, 'Revenue', 'Cost', 'Profit')

Answer 4

A second way of doing it. Not tested (so probably some typos), but doing some SQL to get the data then looping around the details, lobbing them to an object to put out the rows. This will cope with any where a company is missing a data for a year.
Note that you could greatly simplify the SQL if you had a table of years that you are interested in and a table of companies.
<?php
$sql = "SELECT Sub1.Year, Sub2.Company, IFNULL(SomeTable.Revenue, 0) AS aValue, 'Revenue' AS Item
FROM
(
SELECT DISTINCT Year FROM SomeTable
) Sub1
CROSS JOIN
(
SELECT DISTINCT Company FROM SomeTable
) Sub2
LEFT OUTER JOIN SomeTable
ON Sub1.Year = SomeTable.Year
AND Sub2.Company = SomeTable.Company
UNION
SELECT Sub1.Year, Sub2.Company, IFNULL(SomeTable.Cost, 0) AS aValue, 'Cost' AS Item
FROM
(
SELECT DISTINCT Year FROM SomeTable
) Sub1
CROSS JOIN
(
SELECT DISTINCT Company FROM SomeTable
) Sub2
LEFT OUTER JOIN SomeTable
ON Sub1.Year = SomeTable.Year
AND Sub2.Company = SomeTable.Company
UNION
SELECT Sub1.Year, Sub2.Company, IFNULL(SomeTable.Profit, 0) AS aValue, 'Profit' AS Item
FROM
(
SELECT DISTINCT Year FROM SomeTable
) Sub1
CROSS JOIN
(
SELECT DISTINCT Company FROM SomeTable
) Sub2
LEFT OUTER JOIN SomeTable
ON Sub1.Year = SomeTable.Year
AND Sub2.Company = SomeTable.Company
ORDER BY Company, FIELD(Item, 'Revenue', 'Cost', 'Profit'), Year";
$query = $db->query($sql) or die($db->error()) ;
if ($row = $this->db->fetchAssoc())
{
echo "<table>";
$PrevCompany = $row['Company'];
$PrevItem = $row['Item'];
$aLine = new ProcessLine($PrevCompany, $PrevItem, true);
do
{
if ($PrevCompany != $row['Company'] or $PrevItem != $row['Item'])
{
unset($aLine);
$PrevCompany = $row['Company'];
$PrevItem = $row['Item'];
$aLine = new ProcessLine($PrevCompany, $PrevItem);
}
$aLine->Assign_Detail($row['Year'], $row['aValue'])
} while($row = $this->db->fetchAssoc());
unset($aLine);
echo "</table>";
}
class ProcessLine
{
private $Company;
private $Item;
private $row_details = array();
private $FirstRow = false
public __CONSTRUCT($Company, $Item, $FirstRow=false)
{
$this->Company = $Company;
$this->Item = $Item;
}
public __DESTRUCT()
{
if ($this->Firstrow)
{
echo "<tr><th>".$this->Company."</th><th>".$this->Item."</th>";
foreach($row_details AS $row_year=>$row_value)
{
echo "<th>$row_year</th>";
}
echo "</tr>";
}
echo "<tr><td>".$this->Company."</td><td>".$this->Item."</td><td>".implode("</td><td>", $row_details)."</td></tr>";
}
public Assign_Detail($in_year, $in_value)
{
$row_details[$in_year] = $in_value;
}
}
?>