MySQL に電子メール アドレスがないクエリ
<p>
我有一个表（datas）：
<table class="s-table">
<thead>
<tr>
<th>line</th>
<th>account</th>
<th>name</th>
<th>email</th>
</tr>
</thead>
<tbody>
<tr>
<td>1</td>
<td>1000</td>
<td>Reyes VonRueden Sr.</td>
<td>sharon51@yahooo.com</td>
</tr>
<tr>
<td>1</td>
<td>1000</td>
<td>Dr. Elena Bartell V</td>
<td></td>
</tr>
<tr>
<td>1</td>
<td>1000</td>
<td>Lucio Wehner</td>
<td></td>
</tr>
<tr>
<td>2</td>
<td>1000</td>
<td>April Hansen</td>
<td></td>
</tr>
<tr>
<td>2</td>
<td>1000</td>
<td>Amy Waelchi</td>
<td>hegmann.khalid@yahooo.com</td>
</tr>
<tr>
<td>2</td>
<td>1000</td>
<td>Tremaine Cassin</td>
<td></td>
</tr>
<tr>
<td>3</td>
<td>1000</td>
<td>Susana White Jr.</td>
<td>jfay@hotmailses.com</td>
</tr>
<tr>
<td>3</td>
<td>1000</td>
<td>Roxane Hoeger</td>
<td></td>
</tr>
<tr>
<td>3</td>
<td>1000</td>
<td>Prof. Eric Boehm</td>
<td></td>
</tr>
<tr>
<td><strong>4</strong></td>
<td><strong>1000</strong></td>
<td><strong>Miles Considine</strong></td>
<td>** **</td>
</tr>
<tr>
<td><strong>4</strong></td>
<td><strong>1000</strong></td>
<td><strong>Araceli Effertz</strong></td>
<td>** **</td>
</tr>
<tr>
<td><strong>4</strong></td>
<td><strong>1000</strong></td>
<td><strong>Prof. Adolph Pacocha</strong></td>
<td>** **</td>
</tr>
<tr>
<td>5</td>
<td>1000</td>
<td>Prof. Rafaela Hills</td>
<td>sydney20@gradyesses.com</td>
</tr>
<tr>
<td>5</td>
<td>1000</td>
<td>Delta Becker</td>
<td></td>
</tr>
<tr>
<td>5</td>
<td>1000</td>
<td>Aditya Ratke</td>
<td>julian28@yahooes.com</td>
</tr>
<tr>
<td>6</td>
<td>1000</td>
<td>Miss Elaina Aufderhar Sr.</td>
<td>royal.predovic@connellyses.com</td>
</tr>
<tr>
<td>6</td>
<td>1000</td>
<td>Miss Stephanie Russel IV</td>
<td></td>
</tr>
<tr>
<td>6</td>
<td>1000</td>
<td>Dr. Ramiro Marks IV</td>
<td>wrice@yahooes.com</td>
</tr>
<tr>
<td><strong>7</strong></td>
<td><strong>1000</strong></td>
<td><strong>Garfield Kozey</strong></td>
<td>** **</td>
</tr>
<tr>
<td><strong>7</strong></td>
<td><strong>1000</strong></td>
<td><strong>Gene Hilpert</strong></td>
<td>** **</td>
</tr>
</tbody>
</table>
</p><p>线路和账户字段清楚地定义了一个客户。</p><p>
姓名字段是一个工人。</p><p>
我正在寻找没有电子邮件地址的客户（线路+账户）。</p><p>
在这种情况下，结果是：4-1000和7-1000。</p>
<p>我可以用两个查询和Excel来解决这个问题，但在MySQL中会更快。</p>
<p>如果您能帮忙，谢谢；）</p>
