SELECT a.COLUMN_NAME
FROM all_cons_columns a INNER JOIN all_constraints c
     ON a.constraint_name = c.constraint_name
WHERE c.table_name = 'TBL'
  AND c.constraint_type = 'P';

SELECT     X.NAME AS INDEXNAME,
           COL_NAME(IC.OBJECT_ID,IC.COLUMN_ID) AS COLUMNNAME
FROM       SYS.INDEXES  X
INNER JOIN SYS.INDEX_COLUMNS  IC
        ON X.OBJECT_ID = IC.OBJECT_ID
       AND X.INDEX_ID = IC.INDEX_ID
WHERE      X.IS_PRIMARY_KEY = 1
  AND      OBJECT_NAME(IC.OBJECT_ID)='YOUR_TABLE'

show index from TABLE where Key_name = 'PRIMARY' ;

SELECT k.COLUMN_NAME
FROM information_schema.table_constraints t
LEFT JOIN information_schema.key_column_usage k
USING(constraint_name,table_schema,table_name)
WHERE t.constraint_type='PRIMARY KEY'
    AND t.table_schema=DATABASE()
    AND t.table_name='owalog';