delete duplicate rows and need to keep one from all of them in mysql

34,360

Solution 1

DELETE  a
FROM    tableA a
        LEFT JOIN
        (
            SELECT MIN(ID) ID, Name, Phone
            FROM    TableA
            GROUP   BY Name, Phone
        ) b ON  a.ID = b.ID AND
                a.NAme = b.Name AND
                a.Phone = b.Phone
WHERE   b.ID IS NULL

After you have executed the delete statement, enforce a unique constraint on the column so you cannot insert duplicate records again,

ALTER TABLE TableA ADD CONSTRAINT tb_uq UNIQUE (Name, Phone)

Solution 2

DELETE
FROM Table
WHERE Table.id NOT IN  (  
    SELECT MIN(idTable) idtable
    FROM idTable
    GROUP BY name, phone)
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Neel
Author by

Neel

Updated on March 22, 2020

Comments

  • Neel
    Neel about 4 years

    I want to delete duplicate rows based on two columns but need to keep 1 row all of them.

    Duplicate rows can be more than two rows like,

    ID  NAME PHONE
    --  ---- ----
    1   NIL  1234 
    2   NIL  1234 
    3   NIL  1234 
    4   MES  5989
    

    I want to delete any of 2 rows from above 3 and keep 1 row.