Question: I have a `MySQL` table like:

```
ID, Col1, Col2, Col3, Col4, etc...

```

ID is a **`primary key`** and has been working since the table's creation.

What I want to do is delete all but one records where all the other columns are identical.

Answer: 
```
DELETE DupRows.*
FROM MyTable AS DupRows
   INNER JOIN (
      SELECT MIN(ID) AS minId, col1, col2
      FROM MyTable
      GROUP BY col1, col2
      HAVING COUNT(*) > 1
   ) AS SaveRows ON SaveRows.col1 = DupRows.col1 AND SaveRows.col2 = DupRows.col2
      AND SaveRows.minId <> DupRows.ID;

```

Of course you have to extend col1, col2 in all three places to all columns.

Edit: I just pulled this out of a script I keep and re-tested, it executes in MySQL.
1. `RENAME TABLE [table w/ duplicates] TO [temporary table name]`
2. Create an identical table with the original table name which contained the duplicates.
3. `INSERT INTO [new table] SELECT DISTINCT * FROM [old table with duplicates]`
4. Delete the temporary tables.