how to remove duplicates in mysql select query code example

Example 1: mysql remove duplicates

DELETE FROM table_name WHERE id 
       NOT IN ( SELECT id FROM table_name 
                   GROUP BY field_1, field_2)

Example 2: mysql delete older duplicates

delete test
   from test
  inner join (
     select max(id) as lastId, email
       from test
      group by email
     having count(*) > 1) duplic on duplic.email = test.email
  where test.id < duplic.lastId;

Example 3: mysql remove duplicates

DELETE t1 FROM contacts t1
INNER JOIN contacts t2 
WHERE 
    t1.id < t2.id AND 
    t1.email = t2.email;Code language: SQL (Structured Query Language) (sql)

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Sql Example

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