Mysql remove duplicates

DELETE c1 FROM tablename c1
INNER JOIN tablename c2 
WHERE
    c1.id > c2.id AND 
    c1.unique_field = c2.unique_field;

Mysql delete older duplicates

DELETE FROM CONTACTS
WHERE ID NOT IN
      (SELECT *
       FROM (SELECT max(ID)		
             FROM CONTACTS
             GROUP BY EMAIL) t);
 -- ⇓ Test it ⇓ (Fiddle source link)

Source: sqlfiddle.com

Select where duplicate mysql

SELECT 
    col1, COUNT(col1),
    col2, COUNT(col2)
FROM
    table_name
GROUP BY 
    col1, 
    col2
HAVING 
       (COUNT(col1) > 1) AND 
       (COUNT(col2) > 1);

Source: mysqltutorial.org

How to delete all duplicate items in mysql

DELETE FROM FriendsData WHERE fID 
       NOT IN ( SELECT fID FROM FriendsData 
                   GROUP BY UserID, FriendsUserID, IsSpecial, CreatedBy)

Mysql delete duplicate rows but keep one

DELETE c1 FROM contacts c1
INNER JOIN contacts c2 
WHERE
    c1.id > c2.id AND 
    c1.email = c2.email;

Source: mysqltutorial.org

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)

-1

Source: mysqltutorial.org

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