Using the QUERY command will use the "@" character as a wildcard. However, this is not always the desired behavior. In cases where a query should treat the "@" character as its literal character and not as a wildcard, the QUERY BY FORMULA command can be used. Below is an example.

Say there is a "Users" table with a "username" field containing three records with the following usernames:
- user@
- user1
- user2

Executing the following lines of code will return all three records in the selection:

$username:="user@" QUERY([Users];[Users]username=$username)

However, using the command QUERY BY FORMULA as follows will return only the one record where the username is "user@":

$username:="user@" QUERY BY FORMULA([Users];\   Generate digest([Users]username;MD5 Digest)=Generate digest($username;MD5 Digest))