You'll be *much* better off doing this in Twig or PHP, as there is a lot of logic involved in fetching the content of live entries. But since you asked, here is an SQL query that joins 3 tables to get you the title of all live entries.

```sql
SELECT title FROM content
INNER JOIN entries ON entries.id = content.elementId
INNER JOIN elements ON elements.id = content.elementId
WHERE enabled = 1
AND draftId IS NULL AND revisionId IS NULL AND dateDeleted IS NULL
AND postDate <= now() 
AND (expiryDate IS NULL OR expiryDate > now())
```

Some of the above logic was referenced from the [EntryQuery](https://github.com/craftcms/cms/blob/c5730385b295fc383002832435e9813bdcad98d4/src/elements/db/EntryQuery.php#L874-L886) class.