Topic 6

The ________ operator is used to combine the output from multiple queries into a single result table.

• INTERSECT

• DIVIDE

• COLLATE

• UNION

A ________ is a temporary table used in the FROM clause of an SQL query.

• correlated subquery

• derived table

• view table

• trigger

In order for two queries to be UNION-compatible, they must:

• both have the same number of lines in their SQL statements.

• both output compatible data types for each column and return the same number of rows.

• both return at least one row.

• both return exactly one row.

The UNION clause is used to:

• combine the output from multiple queries into a single result table.

• join two tables together to form one table.

• find all rows that do not match in two tables.

• find all rows that are in one table, but not the other.

Establishing IF-THEN-ELSE logical processing within an SQL statement can be accomplished by:

• using the if-then-else construct.

• using the immediate if statement.

• using the CASE key word in a statement.

• using a subquery.

All of the following are guidelines for better query design EXCEPT:

• understand how indexes are used in query processing.

• use a lot of self-joins.

• write simple queries.

• retrieve only the data that you need.

A join operation:

• brings together data from two different fields.

• causes two tables with a common domain to be combined into a single table or view.

• causes two disparate tables to be combined into a single table or view.

• is used to combine indexing operations.

A join in which the joining condition is based on equality between values in the common columns is called a(n):

• equi-join.

• unilateral join.

• natural join.

• both A and C.

The following code is an example of a(n): SELECT Customer_T.CustomerID, Order_T.CustomerID, CustomerName, OrderID FROM Customer_T, Order_T WHERE Customer_T.CustomerID = Order_T.CustomerID;

• equi-join.

• subquery.

• Full Outer JOIN.

• Right Outer JOIN.

The following code would include: SELECT Customer_T.CustomerID,CustomerName, OrderID FROM Customer_T RIGHT OUTER JOIN Order_T ON Customer_T.CustomerID = Order_T.CustomerID;

• all rows of the Order_T Table regardless of matches with the Customer_T Table.

• all rows of the Customer_T Table regardless of matches with the Order_T Table.

• only rows that match both Customer_T and Order_T Tables.

• only rows that don't match both Customer_T and Order_T Tables.