SQL: Join tables on substrings

Question

I have a table A with the string-column a and a table B with the string-column b. a is a substring of b.

Answer 1

set an inner join on a substring(4 letters) of FIELD1 of table TABLE1 with FIELD1 of table TABLE2

select TABLE1.field1,TABLE2.field1 from TABLE1 inner join TABLE2 on substring(TABLE1.field1,2,5)=TABLE2.field1