How can I convert a Unix timestamp to a formatted date-time string in Databricks SQL?
You can use the `from_unixtime()` function to convert a Unix timestamp to a formatted date-time string in Databricks SQL. The function takes a BIGINT expression representing seconds elapsed since 1969-12-31 at 16:00:00 and an optional STRING expression with a valid format. If the format is omitted, 'yyyy-MM-dd HH:mm:ss' is used.

Here's an example:

```sql
SELECT from_unixtime(0, 'yyyy-MM-dd HH:mm:ss');
```

This will return the date-time string '1969-12-31 16:00:00' for the Unix timestamp 0.