How to get the number of deleted rows in PostgreSQL?

You can use RETURNING clause:

DELETE FROM table WHERE condition IS TRUE RETURNING *;

After that you just have to check number of rows returned. You can streamline it with CTE:

WITH deleted AS (DELETE FROM table WHERE condition IS TRUE RETURNING *) SELECT count(*) FROM deleted;

This should return just the number of deleted rows.

in Python using psycopg2, the rowcount attribute can be used. Here is an example to find out how many rows were deleted...

cur = connection.cursor()
try:
    cur.execute("DELETE FROM table WHERE col1 = %s", (value,))
    connection.commit()
    count = cur.rowcount
    cur.close()
    print("A total of %s rows were deleted." % count)
except:
    connection.rollback()
    print("An error as occurred, No rows were deleted")

GET DIAGNOSTICS is used to display number of modified/deleted records.

Sample code

CREATE OR REPLACE FUNCTION fnName()
  RETURNS void AS
$BODY$
        declare
         count numeric;
       begin
              count := 0;
            LOOP
             -- condition here update or delete;
             GET DIAGNOSTICS count = ROW_COUNT;
             raise notice 'Value: %', count;
             end loop;
        end;
$BODY$a

This should be simple in Java.

Statement stmt = connection.createStatement();
int rowsAffected = stmt.executeUpdate("delete from your_table");
System.out.println("deleted: " + rowsAffected);

See java.sql.Statement.