Allows you to run SQL against the database. The SQL statement must return exactly one column and one row of data in the results. If one row is returned, it means that the lint has detected a problem. However, if no rows of data are returned, it means that there are no issues. 
Example configuration:

```yaml
- id: schemacrawler.tools.linter.LinterCatalogSql
  config:
    message: message for SQL catalog lint
    sql: SELECT TOP 1 1 FROM INFORMATION_SCHEMA.TABLES
```
