<p>Given a couple of simple tables like so:</p>

<pre><code>create table R(foo text);
create table S(bar text);
</code></pre>

<p>If I were to union them together in a query, what do I call the column?</p>

<pre><code>select T.????
from (
    select foo
    from R
    union
    select bar
    from S) as T;
</code></pre>

<p>Now, in mysql, I can apparently refer to the column of T as 'foo' -- the name of the matching column for the first relation in the union. In sqlite3, however, that doesn't seem to work. Is there a way to do it that's standard across all SQL implementations?</p>

<p>If not, how about just for sqlite3?</p>

<p>Correction: sqlite3 does allow you to refer to T's column as 'foo' after all! Oops!</p>

Try to give an alias to columns;
```
```
select T.Col1
from (
    select foo as Col1
    from R
    union
    select bar as Col1
    from S) as T;
```
```
or If the name of column is not necessary then T.* will be enough.