CST363 Week 6

We covered additional SQL and SQLPlus commands including grouping and subqueries. The GROUP BY clause is used in collaboration with the SELECT statement to arrange identical data into groups. An example of this command is:

SELECT column1, column2
FROM table_name
WHERE [ conditions ]
GROUP BY column1, column2
ORDER BY column1, column2

A subquery is a query within another query and embedded within the WHERE clause. A subquery is used to return data that will be used in the main query as a condition to further restrict the data to be retrieved. An example of this command is:

SELECT column_name [, column_name ]
FROM   table1 [, table2 ]
WHERE  column_name OPERATOR
      (SELECT column_name [, column_name ]
      FROM table1 [, table2 ]
      [WHERE])

We also touched on SQL I/O. As a side note, it would be helpful if the class covered more troubleshooting commands like DESCRIBE as well.