The query below returns the foreign key constraint columns defined in the user databases (schemas).
Query
select concat(fks.constraint_schema, '.', fks.table_name) as foreign_table,
       '->' as rel,
       concat(fks.unique_constraint_schema, '.', fks.referenced_table_name)
              as primary_table,
       kcu.ordinal_position as no,
       kcu.column_name as fk_column_name,
       '=' as 'join',
       kcu.referenced_column_name as pk_column_name,
       fks.constraint_name as fk_constraint_name
from information_schema.referential_constraints fks
join information_schema.key_column_usage kcu
     on fks.constraint_schema = kcu.table_schema
     and fks.table_name = kcu.table_name
     and fks.constraint_name = kcu.constraint_name
where kcu.table_schema not in('information_schema','sys',
                              'mysql', 'performance_schema')
--    and fks.constraint_schema = 'database name'
order by fks.constraint_schema,
         fks.table_name,
         kcu.ordinal_position;
Note: if you need the information for a specific database (schema), then uncomment the table_schema condition and provide your database name.
Columns
- foreign_table - foreign table name with database (schema) name
- rel - relationship symbol implicating direction
- primary_table - primary (referenced) table name with database (schema) name
- no - id of the column in the key. Single column keys always have 1, composite keys have 1, 2, ... n for each column of the key
- fk_column_name - foreign table column
- join - "=" symbol indicating the joining operation for a pair of columns
- pk_column_name - primary (referenced) table column
- fk_constraint_name - foreign key constraint name
Rows
- One row: represents one foreign key column. If the foreign key is composed of several columns (composite key), each column appears separately
- Scope of rows: all foreign keys in a database (schema) and its columns
- Ordered by: foreign table database (schema) name, table name and column ordinal position in the key
Sample results

 
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                 
                                                             
                                                             
                                                             
                                                             
                                                                 
                                                             
                                                             
                                                                 
                                                             
                                                             
                                                             
                                                             Bart Gawrych
                                                                        Bart Gawrych
                                 MariaDB
                                                                MariaDB
                                 SQL Server
                                                                                                SQL Server
                                             Azure SQL Database
                                                                                                Azure SQL Database
                                             Amazon Redshift
                                                                                                Amazon Redshift
                                             IBM Db2
                                                                                                IBM Db2
                                             Teradata
                                                                                                Teradata
                                             Vertica
                                                                                                Vertica
                                             PostgreSQL
                                                                                                PostgreSQL
                                             MySQL
                                                                                                MySQL