I think you would probably have to provide some external programming to solve this.  I can't see a way of putting a SQL solution together.

 

Using external programming (any of the usual development systems) you can get a list of tables, together with a list of fields they contain, and the data types they have.  You can then programmatically construct SQL (for each table) something like:

select * from <this table> where <field1>||<field2>|| etc   like ‘%<the string required>%’

 

It might take a long time though.

 

Neville Richards