How can I convert a string representing a date and time into a date data type in Databricks SQL, using a specific date format?
You can use the `to_date` function in Databricks SQL to convert a string representing a date and time into a date data type. The function takes two arguments: the string expression to be converted and an optional format string. If the format string is not provided, the function is equivalent to casting the expression to a date data type.

Here's an example of how to use the `to_date` function with a specific date format:
```sql
SELECT to_date('2016-12-31 04:17:52', 'yyyy-MM-dd HH:mm:ss') AS converted_date;
```
In this example, the `to_date` function converts the string `'2016-12-31 04:17:52'` to a date data type using the format string `'yyyy-MM-dd HH:mm:ss'`. The resulting date is `'2016-12-31'`.

Note that if the format string is malformed or its application does not result in a well-formed date, the function will raise an error. However, if the `spark.sql.ansi.enabled` configuration is set to `false`, the function will return `NULL` instead of an error for malformed dates.