delete duplicate mysql 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 duplicate rows but keep one
DELETE c1 FROM contacts c1
INNER JOIN contacts c2
WHERE
c1.id > c2.id AND
c1.email = c2.email;
Example 3: 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)
Example 4: mysql delete duplicate rows
DELETE FROM table_name
WHERE
id IN (
SELECT
id
FROM (
SELECT
id,
ROW_NUMBER() OVER (
PARTITION BY field_1
ORDER BY field_1) AS row_num
FROM
table_name
) t
WHERE row_num > 1
);