I work on a dataset with three different columns: `pile`, `position` and `info`.

There is no duplicate in the database, but it can happen, that for one combination of `pile` and `position` there is one or two different texts in the info column. And those are the entries I tried to find.

I tried the following

```
SELECT COUNT(DISTINCT(`pile`, `position`)) FROM db;

```

But received an error message

```
ERROR 1241 (21000): Operand should contain 1 column(s)

```

Is there a way to find distinct combinations of values in two columns?