SQL unpivot row to N rows (based on column value) - sql

Question

I have a table looking like the example below, and trying to UNPIVOT the table to hold only ONE link per row, and adding an info column, based on the UNPIVOT.
I managed to get partly to my desired result, but need a bit help for the last part. I have this Query so far:
SELECT Theme, Area, URL
FROM
(
SELECT Theme, Area, URL_1, URL_2, URL_3
FROM table
) AS a
UNPIVOT
(
URL FOR URLs IN (URL_1, URL_2, Url_3)
) AS b WHERE URL <> '';
How to add this extra Column, with info based on the URL?
Thank you in advance.
<h1>Have</h1>
<table border="1" cellpadding="1" cellspacing="2">
<tr>
<th>Theme</th>
<th>Area</th>
<th>URL_1</th>
<th>URL_2</th>
<th>URL_3</th>
</tr>
<tr>
<td>A</td>
<td>B</td>
<td>Some URL</td>
<td></td>
<td></td>
</tr>
<tr>
<td>A</td>
<td>C</td>
<td>Some URL</td>
<td>Some URL</td>
<td></td>
</tr>
<tr>
<td>D</td>
<td>B</td>
<td>Some URL</td>
<td>Some URL</td>
<td></td>
</tr>
<tr>
<td>B</td>
<td>D</td>
<td>Some URL</td>
<td>Some URL</td>
<td>Some URL</td>
</tr>
</table>
<h1>Would like</h1>
<table border="1" cellpadding="1" cellspacing="2">
<tr>
<th>Theme</th>
<th>Area</th>
<th>URL</th>
<th>Type</th>
</tr>
<tr>
<td>A</td>
<td>B</td>
<td>Some URL</td>
<td>1</td>
</tr>
<tr>
<td>A</td>
<td>C</td>
<td>Some URL</td>
<td>1</td>
</tr>
<tr>
<td>A</td>
<td>C</td>
<td>Some URL</td>
<td>2</td>
</tr>
<tr>
<td>D</td>
<td>B</td>
<td>Some URL</td>
<td>1</td>
</tr>
<tr>
<td>D</td>
<td>B</td>
<td>Some URL</td>
<td>2</td>
</tr>
<tr>
<td>B</td>
<td>D</td>
<td>Some URL</td>
<td>1</td>
</tr>
<tr>
<td>B</td>
<td>D</td>
<td>Some URL</td>
<td>2</td>
</tr>
<tr>
<td>B</td>
<td>D</td>
<td>Some URL</td>
<td>3</td>
</tr>
</table>
<h1>What I got so far</h1>
<table border="1" cellpadding="1" cellspacing="2">
<tr>
<th>Theme</th>
<th>Area</th>
<th>URL</th>
</tr>
<tr>
<td>A</td>
<td>B</td>
<td>Some URL</td>
</tr>
<tr>
<td>A</td>
<td>C</td>
<td>Some URL</td>
</tr>
<tr>
<td>A</td>
<td>C</td>
<td>Some URL</td>
</tr>
<tr>
<td>D</td>
<td>B</td>
<td>Some URL</td>
</tr>
<tr>
<td>D</td>
<td>B</td>
<td>Some URL</td>
</tr>
<tr>
<td>B</td>
<td>D</td>
<td>Some URL</td>
</tr>
<tr>
<td>B</td>
<td>D</td>
<td>Some URL</td>
</tr>
<tr>
<td>B</td>
<td>D</td>
<td>Some URL</td>
</tr>
</table>

Answer 1

short answer:
SELECT Theme, Area, UrlKind, URL
FROM
(
SELECT Theme, Area, URL_1, URL_2, URL_3
FROM table
) AS a
UNPIVOT
(
URL FOR UrlKind IN (URL_1, URL_2, Url_3)
) AS b WHERE URL <> '';
So name of that column is defined by FOR ... part of unpivot.