Beginning XML Databases (Wrox Beginning Guides)

1. 

Which of these will sort records in a query?

1. ORDER BY

2. WHERE

3. SELECT

4. FROM

5. None of the above

2. 

What will the statement SELECT * FROM CUSTOMER find?

1. All records in the CUSTOMER table

2. The first record in the CUSTOMER table

3. The last two records in the CUSTOMER table

4. All fields in the CUSTOMER table

5. All records and all fields in the CUSTOMER table

3. 

Which of these statements can be used to make changes to data in a database?

1. UPDATE

2. SELECT * FROM ...

3. CREATE TABLE

4. ALTER TABLE

5. INSERT

6. All but b.

4. 

How many tables will this query retrieve records from?

SELECT * FROM TABLE1 CROSS JOIN INNER JOIN TABLE2 USING (ID1) CROSS JOIN TABLE3 LEFT OUTER JOIN TABLE4 USING (ID2);

1. 1

2. 2

3. 3

4. 4

5. 5

1.  

Exercise 1 solution

e. ORDER BY . The ORDER BY clause is added to the end of a query SELECT statement to re-sort records after the WHERE and GROUP BY clauses have been applied to the selected records.

2.  

Exercise 2 solution

e. All records and all fields in the CUSTOMER table. The * (asterisk or star character) means that all fields are retrieved from a table. The lack of a WHERE clause filter or a GROUP BY clause summary means that all records are retrieved. In other words, all the data contents of the entire table are retrieved.

3.  

Exercise 3 solution

f. All but b. Answer f is correct because b is a query that retrieves data from a database. The UPDATE statement changes records in a table. The CREATE TABLE statement creates a new table. The ALTER TABLE changes an existing table. The INSERT statement adds records to a table.

4.  

Exercise 4 solution

d. 4. Answer d is correct because there are three JOIN clauses and four tables shown in the query.