How can I set a variable as an array of values, that would be used in an IN clause?

This works:

```
SELECT *
  FROM TableA
 WHERE Col1 IN ('Value1', 'Value2', 'Value3');

```

But I can't figure out how to create a variable from that manually specified array to use. I want to do something like this:

```
SET values = ('Value1', 'Value2', 'Value3');

SELECT *
  FROM TableA
 WHERE Col1 IN $values;

```

The reported error:
`SQL compilation error: Number of variables on left-hand side of assignment (1) is not equal to the number of values on right-hand side (3)`

So how can I create an arary variable for this purpose?