How to get primary key column in Oracle?

Question

I need to get the name of the primary key column.

In the input, I only have the table name.

Answer 1

Same as the answer from 'Richie' but a bit more concise.

1. Query for user constraints only

   SELECT column_name FROM all_cons_columns WHERE constraint_name = (
     SELECT constraint_name FROM user_constraints 
     WHERE UPPER(table_name) = UPPER('tableName') AND CONSTRAINT_TYPE = 'P'
   );
   

2. Query for all constraints

   SELECT column_name FROM all_cons_columns WHERE constraint_name = (
     SELECT constraint_name FROM all_constraints 
     WHERE UPPER(table_name) = UPPER('tableName') AND CONSTRAINT_TYPE = 'P'
   );