Count where previous record exists in either of two tables I'm trying to COUNT records on one table where both the counted records and their "previous" records exist either in the same table or on another.

The table that I'm sampling has a composite PRIMARY KEY consisting of a bigint and character.  The other table has the same structure.

A "previous" record has the same character and a bigint - 1 as the counted record either on the same table or on the other table.

In pseudo:

counting_table
   character_column
   bigint_column

other_table
   character_column
   bigint_column


counting_table will never have a parallel record on other_table because the parallel record on counting_table is deleted when its primary key equivalent is inserted into other_table.

I thought I could do this with subqueries, but I can't seem to figure out how to access the outer query's data from inside the subquery.

How can my intent be implemented optimally?
Inner join on counting_table.bigint-1 = other_table.bigint and counting_table.char = other_table.char

SELECT * 
FROM counting_table t1 
INNER JOIN other_table t2 
    ON t1.bigint_column-1 = t2.bigint_column 
    AND t1.character_column=t2.character_column