* .at matches any three-character string ending with “at”, including “hat”, “cat”, and “bat”. * [hc]at matches “hat” and “cat”. * [^b]at matches all strings matched by .at except “bat”. * ^[hc]at matches “hat” and “cat”, but only at the beginning [...]
The HAVING clause was added to SQL because the WHERE clause could not be used with aggregate functions. Syntax: SELECT column_name, aggregate_function(column_name) FROM table_name WHERE column_name operator value GROUP BY column_name HAVING aggregate_function(column_name) operator value Example: SELECT customer,SUM(orderprice) FROM trans_orders GROUP BY customer HAVING SUM(orderprice)
