select COLUMN_NAME,INDEX_NAME
from INFORMATION_SCHEMA.STATISTICS
where TABLE_SCHEMA = 'my_schema_name'
and TABLE_NAME='my_table_name'
and INDEX_NAME='PRIMARY'
See also:
How to get primary key of a table from PostgreSQL
How to get primary key of a table from SQLite
How to get primary key of a table from SQL Server
How to get primary key of a table from DB2
How to get primary key of a table from Oracle
Some MySQL tools you can try: https://www.withdata.com/mysql/
