As other technical tips have shown (see below), the @ symbol is used as a "wildcard" character when used in queries. On the other hand, the @ symbol in the Find dialog box (or Find in Database) in the Design Environment will be treated as a regular character. Therefore, do not be surprised if your search returns 0 results when you include the @ symbol.

Related Techtips:

https://kb.4d.com/assetid=4778
https://kb.4d.com/assetid=42090