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 |
+----+------------------+
# Write your MySQL query statement below delete from Person where Id not in
(
select Id from
(
select Id,
if(STRCMP(@prev, Email)=0, false, true) as Diff,
@prev := Email from
(select * from Person p2 order by Email, Id asc) x,
(select @prev := '') y
) t where t.Diff=true
)