Day 3

Quiz

1:What function enables you to provide a value for nulls?
A1: The function you would use to determine whether a column is NULL and then replace it with a value is the ISNULL() function.
2:What is the result of this query?
Use Pubs
Select 'My name is '+ au_fname
From authors
Where au_id = '172-32-1176'

A2: The first name of the author with this au_id would be appended to the string, "My name is ". The output would be
My name is Johnson

3:What column name is displayed by this query?
Use Pubs
Select au_fname as 'First Name'
From authors

A3: Answer: The column name that would be displayed is
First Name

4:What would be the result of the following query?
Use Pubs
Select 'My price is '+ price
From titlesWhere title like '%Computer%'

A4: This was really a trick question. The query will produce an error message only because the price column data type is Money and you are asking to concatenate it with a string constant. The error message is
Server: Msg 260, Level 16, State 1, Line 2
 Disallowed implicit conversion from data type varchar
 to data type money, table 'pubs.dbo.titles',
 column 'price'. Use the CONVERT function to run this query.

Exercises

1:When was the first employee hired by Northwind?
A1: The first employee who was hired will have the lowest or minimum date in the hiredate column of the employees table:
Select min(hiredate)
From Employees

Results:

------------------------------------------------------
1992-04-01 00:00:00.000

(1 row(s) affected)

2:What is today's date and what day of the week is it?
A2: You would use the GETDATE() function to retrieve today's date. Then, to get the day of the week, you could use either the DATEPART() or DATENAME() functions. The SELECT statement you would use is as follows:
Select getdate(), datepart(dw, getdate()), datename(dw, getdate())

Results:

--------------------------- ----------- ------
2000-10-08 13:11:09.723     1           Sunday
(1 row(s) affected)

3:How many hours until New Year's Day?
A3: The answer to this question is calculated by asking for the DATEDIFF() between now and 1/1/2002. To specify hours in the function by using the hh DATEPART() code:
select datediff(hh,getdate(), '1/1/2002')

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