1. Functions and Joins
Objectives
In this lesson, you will learn to:
Use functions
Use different types of joins
©NIIT SQL/Lesson 3/Slide 1 of 49

2. Functions and Joins
3.D.1 Displaying Data in Upper Case Using String
Functions
A report containing the newspaper name, the name of the
contact person, and the telephone numbers is required to
contact various newspapers to place an advertisement. The
newspaper name should be displayed in uppercase.
©NIIT SQL/Lesson 3/Slide 2 of 49

3. Functions and Joins
Task List
Create a format for the query output
Draft the query
Execute the query
Verify that the query output is as per the required results
©NIIT SQL/Lesson 3/Slide 3 of 49

4. Functions and Joins
Create a format for the query output
Result:
The output required in the report is the newspaper name
(in upper case), the contact person, and the telephone
number from the Newspaper table
The column headings in the report are
cNewspaperName, vContactPerson, and cPhone
©NIIT SQL/Lesson 3/Slide 4 of 49

5. Functions and Joins
Draft the query
String Functions: Are used to format data as per specific
requirements
Syntax
SELECT function_name (parameters)
Result:
The information is available in the Newspaper table
The string function to be used to display the names of
newspapers in uppercase is UPPER
Therefore, the query using the SELECT statement should
be:
SELECT 'Newspaper Name'=UPPER
(cNewspaperName), vContactPerson, cPhone
FROM Newspaper
©NIIT SQL/Lesson 3/Slide 5 of 49

6. Functions and Joins
Execute the query
Action:
In the Query Analyzer window, type:
Execute the query
©NIIT SQL/Lesson 3/Slide 6 of 49

7. Functions and Joins
Verify that the query output is as per the required
results
Check whether:
All the required rows are displayed
The newspaper names are displayed in upper case
©NIIT SQL/Lesson 3/Slide 7 of 49

8. Functions and Joins
Just a Minute...
The names, addresses, and phone numbers of the
recruitment agencies in Houston are required. However, only
the first 10 characters of the address should be displayed.
©NIIT SQL/Lesson 3/Slide 8 of 49

9. Functions and Joins
3.D.2 Adding Days to a Date Using Date Functions
The proposed deadline for campus recruitment is 10 days from
the start date of the recruitment process. A report containing
the college code, the start date for recruitment, and the
proposed deadline for all colleges the company is visiting
needs to be displayed.
©NIIT SQL/Lesson 3/Slide 9 of 49

10. Functions and Joins
Task List
Create a format for the query output
Draft the query
Execute the query
Verify that the query output is as per the required results
©NIIT SQL/Lesson 3/Slide 10 of 49

11. Functions and Joins
Create a format for the query output
Result:
The output required in the report is the college code, the
recruitment start date, and the proposed deadline
The column headings of the report are cCollegeCode,
dRecruitmentStartDate, and ProposedDeadline, which is
10 days from the start date
©NIIT SQL/Lesson 3/Slide 11 of 49

12. Functions and Joins
Draft the query
Date functions: Are used to manipulate datetime values,
perform arithmetic operations, and perform date parsing
(extract components like the day, the month, and the year)
Syntax
SELECT date_function (parameters)
Result:
The required information is available in the
CampusRecruitment table
The date function to be used is DATEADD
©NIIT SQL/Lesson 3/Slide 12 of 49

13. Functions and Joins
Draft the query (Contd.)
Therefore, the query using the SELECT statement should
be:
SELECT cCollegeCode, dRecruitmentStartDate,
'Proposed Deadline' = DATEADD(dd, 10,
dRecruitmentStartDate)
FROM CampusRecruitment
©NIIT SQL/Lesson 3/Slide 13 of 49

14. Functions and Joins
Execute the query
Action:
In the Query Analyzer window, type the query
Execute the query
©NIIT SQL/Lesson 3/Slide 14 of 49

15. Functions and Joins
Verify that the query output is as per the required
results
Check whether:
All the required rows are displayed
The proposed deadline is 10 days from the start date
©NIIT SQL/Lesson 3/Slide 15 of 49

16. Functions and Joins
Just a Minute...
A schedule for interviews is required. The name of the candidate,
the interviewer’s employee code, the date, and the weekday of
the interview are to be printed in alphabetical order of candidate
names in the following format:
Candidate Name Interviewer Code Date Week Day
©NIIT SQL/Lesson 3/Slide 16 of 49

17. Functions and Joins
3.D.3 Rounding off Values Using Mathematical
Functions
The test scores of candidates have been declared. Helen
White has scored 79.9 marks, and she is to be informed of the
same. Her first name, telephone number, and score have to be
displayed. The score should be rounded off to the nearest
integer.
©NIIT SQL/Lesson 3/Slide 17 of 49

18. Functions and Joins
Task List
Create a format for the query output
Draft the query
Execute the query
Verify that the query output is as per the required results
©NIIT SQL/Lesson 3/Slide 18 of 49

19. Functions and Joins
Create a format for the query output
Result:
The output required in the report is the first name,
telephone number, and score of the candidate
The column headings of the report are vFirstName,
cPhone, and Score
©NIIT SQL/Lesson 3/Slide 19 of 49

20. Functions and Joins
Draft the query
Mathematical Functions: Are used to perform numerical
operations on mathematical data
Syntax
ROUND (numeric_expression, length)
Result:
The required information is available in the
ExternalCandidate table
The function to be used is ROUND
©NIIT SQL/Lesson 3/Slide 20 of 49

21. Functions and Joins
Draft the query (Contd.)
Therefore, the query using the SELECT statement should
be:
SELECT vFirstName, cPhone,'Score'=
ROUND(79.9,0)
FROM ExternalCandidate
WHERE vFirstName='Helen'
©NIIT SQL/Lesson 3/Slide 21 of 49

22. Functions and Joins
Execute the query
Action:
In the Query Analyzer window, type:
Execute the query
©NIIT SQL/Lesson 3/Slide 22 of 49

23. Functions and Joins
Verify that the query output is as per the required
results
Check whether the marks are rounded off to the nearest
numeric value
©NIIT SQL/Lesson 3/Slide 23 of 49

24. Functions and Joins
System Functions
System functions provide a method of querying the system
tables of SQL Server
These functions are used to access SQL Server,
databases, or user-related information
They enable quick conversion of system and object
information without writing several queries
©NIIT SQL/Lesson 3/Slide 24 of 49

25. Functions and Joins
Data Conversion
The CONVERT function is used to change data from one
type to another when SQL Server cannot implicitly
understand a conversion
Syntax
CONVERT (datatype [(length)], expression [,
style])
©NIIT SQL/Lesson 3/Slide 25 of 49

26. Functions and Joins
Joins
A join can be defined as an operation that includes the
retrieval of data from more than one table at a time
Syntax
SELECT column_name, column_name [,column_name]
FROM table_name [CROSS|INNER|[LEFT |
RIGHT]OUTER] JOIN table_name
[ON table_name.ref_column_name join_operator
table_name.ref_column_name]
[WHERE search_condition]
©NIIT SQL/Lesson 3/Slide 26 of 49

27. Functions and Joins
Joins (Contd.)
The various types of joins are:
Inner Join
Outer Join
Cross Join
Equi Join
Natural Join
Self Join
©NIIT SQL/Lesson 3/Slide 27 of 49

28. Functions and Joins
3.D.4 Displaying Data From Two Tables Using Inner
Joins
The names of the candidates and their recruitment agencies
are required for an analysis by senior management. A report
displaying these details is to be generated.
©NIIT SQL/Lesson 3/Slide 28 of 49

29. Functions and Joins
Task List
Create a format for the query output
Draft the query
Execute the query
Verify that the query output is as per the required results
©NIIT SQL/Lesson 3/Slide 29 of 49

30. Functions and Joins
Create a format for the query output
Result:
The required output from the query is a list of candidate
names and the names of the recruitment agencies that
sent them
©NIIT SQL/Lesson 3/Slide 30 of 49

31. Functions and Joins
Draft the query
Inner Joins
Syntax
SELECT column_name, column_name
[,column_name]
FROM table_name JOIN table_name
ON table_name.ref_column_name
join_operator table_name.ref_column_name
Cartesian Product: A join that includes more than one table
without any condition in the ON clause creates a cartesian
product between the two tables
©NIIT SQL/Lesson 3/Slide 31 of 49

32. Functions and Joins
Draft the query (Contd.)
Result:
The required information is available in the
ExternalCandidate and RecruitmentAgencies tables
Therefore, the query using the SELECT statement should
be:
SELECT 'Candidate Name' = vFirstName,
'Recruitment Agency' = cName
FROM ExternalCandidate JOIN
RecruitmentAgencies
ON ExternalCandidate.cAgencyCode =
RecruitmentAgencies.cAgencyCode
©NIIT SQL/Lesson 3/Slide 32 of 49

33. Functions and Joins
Execute the query
Action:
In the Query Analyzer window, type the query
Execute the query
©NIIT SQL/Lesson 3/Slide 33 of 49

34. Functions and Joins
Verify that the query output is as per the required
results
Check whether:
The required columns from different tables are displayed
The required rows are displayed
©NIIT SQL/Lesson 3/Slide 34 of 49

35. Functions and Joins
Just a Minute…
The names of candidates and the newspapers they referred
for recruitment advertisements are required for an analysis.
A report displaying these details is to be generated.
©NIIT SQL/Lesson 3/Slide 35 of 49

36. Functions and Joins
3.D.5 Displaying Data From Two Tables Using Outer
Joins
The names of all the external candidates along with the
names of their recruitment agencies, wherever applicable,
are required for an analysis. A report displaying these
details is to be generated.
©NIIT SQL/Lesson 3/Slide 36 of 49

37. Functions and Joins
Task List
Create a format for the query output
Draft the query
Execute the query
Verify that the query output is as per the required results
©NIIT SQL/Lesson 3/Slide 37 of 49

38. Functions and Joins
Create a format for the query output
Result:
The required output from the query is the names of all the
external candidates and their recruitment agencies
(wherever applicable)
©NIIT SQL/Lesson 3/Slide 38 of 49

39. Functions and Joins
Draft the query
Outer Joins
A join can be termed an outer join when the result set
contains all rows from one table and the matching rows
from another
Syntax
SELECT column_name, column_name
[,column_name]
FROM table_name [LEFT | RIGHT] OUTER JOIN
table_name
ON table_name.ref_column_name
join_operator table_name.ref_column_name
©NIIT SQL/Lesson 3/Slide 39 of 49

40. Functions and Joins
Draft the query (Contd.)
Result:
The required information is available in the
ExternalCandidate and RecruitmentAgencies tables
Therefore, the query using the SELECT statement should
be:
SELECT vFirstName, vLastName, cName
FROM ExternalCandidate
LEFT OUTER JOIN RecruitmentAgencies
ON ExternalCandidate.cAgencyCode =
RecruitmentAgencies.cAgencyCode
©NIIT SQL/Lesson 3/Slide 40 of 49

41. Functions and Joins
Execute the query
Action:
In the Query Analyzer window, type:
Execute the query
©NIIT SQL/Lesson 3/Slide 41 of 49

42. Functions and Joins
Verify that the query output is as per the required
results
Action:
Check whether:
® The required columns are displayed
® All rows from the first table are displayed
® The require rows from the second table are displayed
©NIIT SQL/Lesson 3/Slide 42 of 49

43. Functions and Joins
Cross Join
A join that includes more than one table using the keyword
CROSS is called a cross join.
Example
SELECT *
FROM Titles CROSS JOIN Publishers
©NIIT SQL/Lesson 3/Slide 43 of 49

44. Functions and Joins
Equi Join
A join that uses an asterisk (*) sign in the SELECT list and
displays redundant column data in the result set is termed as
an equi join
Example
SELECT *
FROM Sales s JOIN Titles t
ON s.Title_Id = t.Title_Id
JOIN Publishers p
ON t.Pub_Id = p.Pub_Id
©NIIT SQL/Lesson 3/Slide 44 of 49

45. Functions and Joins
Natural Join
A join that restricts the redundant column data from the
result set is known as a natural join
Example
SELECT t.Title, p.Pub_Name
FROM Titles t JOIN Publishers p
ON t.Pub_Id = p.Pub_Id
©NIIT SQL/Lesson 3/Slide 45 of 49

46. Functions and Joins
Self Join
A join is said to be a self join when one row in a table
correlates with other rows in the same table
Example
SELECT t1.title,t2.title , t1.price
FROM titles t1 JOIN titles t2 ON
t1.price=t2.price
WHERE t1.price=2.99
©NIIT SQL/Lesson 3/Slide 46 of 49

47. Functions and Joins
Summary
In this lesson you learned that:
SQL Server uses string functions, which can be used as part
of any character expression.
SQL Server includes date functions for performing date
parsing and date arithmetic.
The CONVERT function is used to change data from one
type to another when SQL Server cannot implicitly
understand a conversion.
SQL Server provides a method of retrieving data from more
than one table using joins.
©NIIT SQL/Lesson 3/Slide 47 of 49

48. Functions and Joins
Summary (Contd.)
In inner join, data from multiple tables is displayed after
comparing values present in a common column. Only rows
with values satisfying the join condition in the common
column are displayed.
A join can be termed an outer join when the result set
contains all rows from one table and the matching rows from
another.
A join that includes more than one table using the keyword
CROSS is called a cross join.
A join that uses an asterisk (*) sign in the SELECT list and
displays redundant column data in the result set is termed as
an equi join.
©NIIT SQL/Lesson 3/Slide 48 of 49

49. Functions and Joins
Summary (Contd.)
A join that restricts the redundant column data from the
result set is known as a natural join.
A join is said to be a self join when one row in a table
correlates with other rows in the same table.
©NIIT SQL/Lesson 3/Slide 49 of 49