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: 
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.
You can run an alter query and achieve this:

```
ALTER IGNORE TABLE tbl_1
ADD UNIQUE INDEX unq_idx(col1, col2, col3);

```

I cant guarantee it will retain the first record among the duplicates, but MySQL usually does that.