1. Write a SELECT statement that returns four columns based on the InvoiceTotal
column of the Invoices table:
Use the CAST function to return the first column as data type decimal with 2
digits to the right of the decimal point.
Use CAST to return the second column as a varchar.
Use the CONVERT function to return the third column as the same data type as
the first column.
Use CONVERT to return the fourth column as a varchar, using style 1.

2. Write a SELECT statement that returns four columns based on the InvoiceDate
column of the Invoices table:
Use the CAST function to return the first column as data type varchar.
Use the CONVERT function to return the second and third columns as a varchar,
using style 1 and style 10, respectively.
Use the CAST function to return the fourth column as data type real.

3. Write a SELECT statement that returns two columns based on the Vendors table.
The first column, Contact, is the vendor contact name in this format: first name
followed by last initial (for example, “John S.”) The second column, Phone, is the
VendorPhone column without the area code. Only return rows for those vendors in
the 559 area code. Sort the result set by first name, then last name.

4. Write a SELECT statement that returns the InvoiceNumber and balance due for
every invoice with a non-zero balance and an InvoiceDueDate that’s less than 30
days from today.

5. Modify the search expression for InvoiceDueDate from the solution for exercise 4.
Rather than 30 days from today, return invoices due before the last day of the current
month.

6. Write a summary query WITH CUBE that returns LineItemSum (which is the sum of
InvoiceLineItemAmount) grouped by Account (an alias for AccountDescription) and
State (an alias for VendorState). Use the CASE and GROUPING function to
substitute the literal value “*ALL*” for the summary rows with null values.

7. (If you have access to the Examples database) Modify the third SELECT statement
shown in figure 8-11 of the text to return a middle name, if present. Add a third
column, Middle, which is null if no middle name is present.