SQL - Select in complex field

I have a table TabCustomer containing a number of fields.

One of these fields is a complex one named externalUser:

{"id":123,"companyID":12,"name":"Paul","surname":"Smith",...}

How can I select all the rows of this tab containing Paul as name in externalUser?

Conceptually,

would be something like SELECT * from tabCustomer WHERE externalUser.name="Paul";

This should work on sqlite as well and I cannot use PL/SQL or similar