  Now we want to write a query that finds out for which shoes currently in the store
    we have the matching shoelaces (color and length) and where the
    total number of exactly matching pairs is greater or equal to two.

</P><PRE
CLASS="PROGRAMLISTING"
>SELECT * FROM shoe_ready WHERE total_avail &gt;= 2;

 shoename | sh_avail | sl_name | sl_avail | total_avail
----------+----------+---------+----------+-------------
 sh1      |        2 | sl1     |        5 |           2
 sh3      |        4 | sl7     |