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<h1>SQL UNION and UNION ALL</h1>
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<h2>UNION</h2>
<p>The UNION command is used to select related information from two
tables, much like the JOIN command. However, when using the UNION command all selected columns need to be of the same data type.</p>
<p><b>Note:</b> With UNION, only distinct values are selected.</p>
<table class="ex" cellspacing="0" border="1" width="100%">
<tr><td>
<pre>SQL Statement 1
UNION
SQL Statement 2</pre>
</td>
</tr>
</table>
<br />
<hr />
<p><b>Employees_Norway</b>:</p>
<table class="ex" cellspacing="0" border="1" width="60%">
<tr>
<th width="25%" align="left">E_ID</th>
<th width="35%" align="left">E_Name</th>
</tr>
<tr>
<td>01</td>
<td>Hansen, Ola</td>
</tr>
<tr>
<td>02</td>
<td>Svendson, Tove</td>
</tr>
<tr>
<td>03</td>
<td>Svendson, Stephen</td>
</tr>
<tr>
<td>04</td>
<td>Pettersen, Kari</td>
</tr>
</table>
<p><b>Employees_USA</b>:</p>
<table class="ex" cellspacing="0" border="1" width="60%">
<tr>
<th width="25%" align="left">E_ID</th>
<th width="35%" align="left">E_Name</th>
</tr>
<tr>
<td>01</td>
<td>Turner, Sally</td>
</tr>
<tr>
<td>02</td>
<td>Kent, Clark</td>
</tr>
<tr>
<td>03</td>
<td>Svendson, Stephen</td>
</tr>
<tr>
<td>04</td>
<td>Scott, Stephen</td>
</tr>
</table>
<br />
<hr />
<h2>Using the UNION Command</h2>
<h3>Example</h3>
<p>List all different employee names in Norway and USA:</p>
<table class="ex" cellspacing="0" border="1" width="100%">
<tr><td><pre>SELECT E_Name FROM Employees_Norway
UNION
SELECT E_Name FROM Employees_USA</pre></td></tr>
</table>
<p><b>Result</b></p>
<table class="ex" cellspacing="0" border="1" width="60%">
<tr>
<th width="35%" align="left"><b>E_Name</b></th>
</tr>
<tr>
<td>Hansen, Ola</td>
</tr>
<tr>
<td>Svendson, Tove</td>
</tr>
<tr>
<td>Svendson, Stephen</td>
</tr>
<tr>
<td>Pettersen, Kari</td>
</tr>
<tr>
<td>Turner, Sally</td>
</tr>
<tr>
<td>Kent, Clark</td>
</tr>
<tr>
<td>Scott, Stephen</td>
</tr>
</table>
<p><b>Note:</b> This command cannot be used to list all employees in Norway and
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