Add SQL solutions to LC196 and LC182

Author: kate-melnykova

LC182-Duplicate-Emails

@@ -0,0 +1,24 @@
+/*
+Write a SQL query to find all duplicate emails in a table named Person.
+
++----+---------+
+| Id | Email   |
++----+---------+
+| 1  | a@b.com |
+| 2  | c@d.com |
+| 3  | a@b.com |
++----+---------+
+For example, your query should return the following for the above table:
+
++---------+
+| Email   |
++---------+
+| a@b.com |
++---------+
+*/
+
+# Write your MySQL query statement below
+SELECT DISTINCT p1.Email
+FROM Person p1,
+    Person p2
+WHERE p1.Email = p2.Email AND p1.Id != p2.Id;

LC196-Delete-Duplicate-Emails

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+/*
+ Write a SQL query to delete all duplicate email entries in a table named Person, keeping only unique emails based on its smallest Id.
+
++----+------------------+
+| Id | Email            |
++----+------------------+
+| 1  | john@example.com |
+| 2  | bob@example.com  |
+| 3  | john@example.com |
++----+------------------+
+Id is the primary key column for this table.
+For example, after running your query, the above Person table should have the following rows:
+
++----+------------------+
+| Id | Email            |
++----+------------------+
+| 1  | john@example.com |
+| 2  | bob@example.com  |
++----+------------------+
+Note:
+
+Your output is the whole Person table after executing your sql. Use delete statement.
+ */
+
+ DELETE p1 FROM Person p1,
+    Person P2
+WHERE
+    p1.Email = p2.Email AND p1.Id > p2.Id;