Initial Commit

priyesh0453 · priyesh0453 · commit 05dc22c6ce49 · 2023-02-04T02:43:20.000+05:30
diff --git a/Easy/196. Delete Duplicate Emails.sql b/Easy/196. Delete Duplicate Emails.sql
@@ -0,0 +1,51 @@
+/*
+Table: Person
+
++-------------+---------+
+| Column Name | Type    |
++-------------+---------+
+| id          | int     |
+| email       | varchar |
++-------------+---------+
+id is the primary key column for this table.
+Each row of this table contains an email. The emails will not contain uppercase letters.
+
+
+Required Query:
+
+1) Delete all the duplicate emails, keeping only one unique email with the smallest id. Note that you are supposed to write a DELETE statement and not a SELECT one.
+
+2) After running your script, the answer shown is the Person table. The driver will first compile and run your piece of code and then show the Person table. The final order of the Person table does not matter.
+
+SQL Schema:
+
+Create table If Not Exists Person (Id int, Email varchar(255))
+Truncate table Person
+insert into Person (id, email) values ('1', 'john@example.com')
+insert into Person (id, email) values ('2', 'bob@example.com')
+insert into Person (id, email) values ('3', 'john@example.com')
+
+Example:
+
+Input: 
+Person table:
++----+------------------+
+| id | email            |
++----+------------------+
+| 1  | john@example.com |
+| 2  | bob@example.com  |
+| 3  | john@example.com |
++----+------------------+
+Output: 
++----+------------------+
+| id | email            |
++----+------------------+
+| 1  | john@example.com |
+| 2  | bob@example.com  |
++----+------------------+
+*/
+
+-- Solution:
+DELETE duplicate
+FROM Person original JOIN Person duplicate
+ON original.email = duplicate.email AND original.id < duplicate.id
