PostgreSQL query, create, delete indexes

- query index 
the SELECT  *  from pg_indexes the WHERE TableName = ' tab1 ' ;    

- creating an index tab1_bill_code_index for the index name, 
the Create  index   tab1_bill_code_index   ON   "db1" .tab1 (bill_code); 

- delete the index 
drop  index tab1_bill_code_index;