MYSQL Group_Concat values into one field but keep multiple rows
<p>I have two tables in MySQL, one containing a single value in each row and the other containing the same values, but they are all combined into a single row. So for example:</p>

<p>Table1:</p>

<pre><code>Column1
a
b
</code></pre>

<p>Table2:</p>

<pre><code>Column1
a,b
</code></pre>

<p>I would like to make a mapping table based off of table 1 so that I can do a join on them.  The result I am looking for would be this:</p>

<pre><code>Column1 |  Column2
a       |  a,b
b       |  a,b
</code></pre>

<p>I have tried this:</p>

<pre><code>SELECT Column1, GROUP_CONCAT(DISTINCT Column1) AS Column2 
FROM Table1
</code></pre>

<p>But it just returns a single row:</p>

<pre><code>Column1 | Column2
a       | a,b
</code></pre>

<p>I have also tried adding a group by clause:</p>

<pre><code>SELECT Column1, GROUP_CONCAT(DISTINCT Column1) AS Column2 
FROM Table1
GROUP BY Column1
</code></pre>

<p>This returns each row, but doesn't concatenate the fields into column2:</p>

<pre><code>Column1 | Column2
a       | a
b       | b
</code></pre>

<p>Is there any way to solve this?  I appreciate the help!</p>