The query below lists all primary keys constraints (PK) in a database (schema).
See also: tables with their primary keys.
Query
select tco.table_schema as database_name,
       tco.constraint_name as pk_name,
       group_concat(kcu.column_name
            order by kcu.ordinal_position
            separator ', ') as columns,
       tco.table_name
from information_schema.table_constraints tco
join information_schema.key_column_usage kcu
     on tco.constraint_schema = kcu.constraint_schema
     and tco.constraint_name = kcu.constraint_name
     and tco.table_name = kcu.table_name
where tco.constraint_type = 'PRIMARY KEY'
      and tco.table_schema not in  ('sys','information_schema',
                                    'mysql', 'performance_schema')
     -- and tco.table_schema  = 'database_name' -- put your database name here
group by tco.table_schema,
         tco.constraint_name,
         tco.table_name
order by tco.table_schema,
         tco.table_name;
Columns
- database_name - PK database (schema) name
- pk_name - PK constraint name
- columns - list of PK columns separated by ','
- table_name - PK table name
Rows
- One row: represents one primary key (table) in a database (schema)
- Scope of rows: all PK constraints in a database (schema)
- Ordered by: database name, table name
Sample results
Sample results for the Sakila database (schema)

 
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                 
                                                             
                                                             
                                                             
                                                             
                                                                 
                                                             
                                                             
                                                                 
                                                             
                                                             
                                                             
                                                             Bart Gawrych
                                                                        Bart Gawrych
                                 MariaDB
                                                                MariaDB
                                 SQL Server
                                                                                                SQL Server
                                             Azure SQL Database
                                                                                                Azure SQL Database
                                             Oracle database
                                                                                                Oracle database
                                             Snowflake
                                                                                                Snowflake
                                             IBM Db2
                                                                                                IBM Db2
                                             PostgreSQL
                                                                                                PostgreSQL
                                             MySQL
                                                                                                MySQL