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1517-find-users-with-valid-e-mails/README.md

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+<h2><a href="https://leetcode.com/problems/find-users-with-valid-e-mails/">1517. Find Users With Valid E-Mails</a></h2><h3>Easy</h3><hr><div class="sql-schema-wrapper__3VBi"><a class="sql-schema-link__3cEg">SQL Schema<svg viewBox="0 0 24 24" width="1em" height="1em" class="icon__1Md2"><path fill-rule="evenodd" d="M10 6L8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"></path></svg></a></div><div><p>Table: <code>Users</code></p>
+
+<pre>+---------------+---------+
+| Column Name   | Type    |
++---------------+---------+
+| user_id       | int     |
+| name          | varchar |
+| mail          | varchar |
++---------------+---------+
+user_id is the primary key (column with unique values) for this table.
+This table contains information of the users signed up in a website. Some e-mails are invalid.
+</pre>
+
+<p>&nbsp;</p>
+
+<p>Write a solution to find the users who have <strong>valid emails</strong>.</p>
+
+<p>A valid e-mail has a prefix name and a domain where:</p>
+
+<ul>
+	<li><strong>The prefix name</strong> is a string that may contain letters (upper or lower case), digits, underscore <code>'_'</code>, period <code>'.'</code>, and/or dash <code>'-'</code>. The prefix name <strong>must</strong> start with a letter.</li>
+	<li><strong>The domain</strong> is <code>'@leetcode.com'</code>.</li>
+</ul>
+
+<p>Return the result table in <strong>any order</strong>.</p>
+
+<p>The result format is in the following example.</p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<pre><strong>Input:</strong> 
+Users table:
++---------+-----------+-------------------------+
+| user_id | name      | mail                    |
++---------+-----------+-------------------------+
+| 1       | Winston   | [email protected]    |
+| 2       | Jonathan  | jonathanisgreat         |
+| 3       | Annabelle | [email protected]     |
+| 4       | Sally     | [email protected] |
+| 5       | Marwan    | quarz#[email protected] |
+| 6       | David     | [email protected]       |
+| 7       | Shapiro   | [email protected]     |
++---------+-----------+-------------------------+
+<strong>Output:</strong> 
++---------+-----------+-------------------------+
+| user_id | name      | mail                    |
++---------+-----------+-------------------------+
+| 1       | Winston   | [email protected]    |
+| 3       | Annabelle | [email protected]     |
+| 4       | Sally     | [email protected] |
++---------+-----------+-------------------------+
+<strong>Explanation:</strong> 
+The mail of user 2 does not have a domain.
+The mail of user 5 has the # sign which is not allowed.
+The mail of user 6 does not have the leetcode domain.
+The mail of user 7 starts with a period.
+</pre>
+</div>