1. Director of Statistical Analysis and Assessment Coordinator
IR 101: Beginning SQL in IR
Kelly Wahl
Director of Statistical Analysis and Assessment Coordinator
UCLA

2. Learning Outcomes Know what SQL is Read a basic SQL SELECT statement
Find online opportunities to learn the language
Recognize examples of SQL syntax and identify what they do
Consider how the results from a SELECT statement can be formatted to meet your needs

3. What is SQL? Structured Query Language (SQL)
Often pronounced “sequel” – because the original acronym was SEQUEL (Structured English QUEry Language)
Developed by IBM in the early 70’s
Changed its name because another company had already trademarked SEQUEL

4. How And When Do We Use SQL?
Its name gives away its purpose: It is a programming language used for managing data and querying databases. SQL has been “structured” to be clear, to sequence commands, to allow options to be pursued, and to block (i.e., to treat groups of statements as one).
Relational Database Management Systems (RDBMS) can use it.
Oracle Database, SQL Server, and MySQL are examples of database software that use this language for data access and management.

5. How Can I Learn SQL on My Own?
Free Tutorials Online:
Give Me Your Info Online (But Free):

6. Properties of Relational Databases
Relational databases are for storing and retrieving related information.
They can be explained with diagrams showing the way the data are “modeled.”
Records are stored as rows in tables that have columns for each variable being stored per case.

7. A Relational Database:
major_degree_table
declared_major_table
term_table
Major | Degree
student_table
ID | Term | Major
Term | Year
ID | Name | Gender
term_enrollment_table
subj_dept_table
ID | Term | Subject | Catlg_No | Grade
Subject | Dept
dept_org_table
ID | Ethnicity
Dept | Org
student_ethnicity_table

8. On a SQL Console: A List of Tables Is Provided
Clicking around Reveals Columns and Properties

9. Commands
Results

10. What Makes a SQL Statement Work?
Syntax
columns
SELECT name
FROM student_table
WHERE gender = ‘Male’
table
filter

11. How to Select Records SELECT name FROM student_table
WHERE gender = ‘Male’
ID | Name | Gender

12. How to Select Records SELECT name FROM student_table
Robert
Frank
Juan
Tongshan
Denzel
SELECT name
FROM student_table
WHERE gender = ‘Male’

13. More Complicated Selections
WILDCARD
(give me all of them)
SELECT *
FROM term_enrollment_table
WHERE (subject = ‘Math’ or
subject = ‘Chem’) and
term = ’17F’ and
substring(catlg_no,2,1) <= ’1’
All Math enrollments and all Chemistry enrollments, in Fall 2017, at the undergraduate course level…

14. More Complicated Selections
FROM term_enrollment_table
WHERE (subject = ‘Math’ or
subject = ‘Chem’) and
term = ’17F’ and
substring(catlg_no,2,1) <= ’1’
ID | Term | Subject | Catlg_No | Grade
17F Math A
17F Chem B
17F Chem B+
17F Chem 0055A C
17F Math A
. . .

15. ‘0032A’ ‘0205’ Returns: ‘0’ Returns: ‘2’ Selected? YES Selected? NO
substring(catlg_no,2,1) <= ’1’
‘0032A’
‘0205’
Returns: ‘0’
Returns:
‘2’
Selected? YES
Selected? NO

16. Little Aggregated Reports
SELECT subject,
COUNT(subject) enrollments
FROM term_enrollment_table
WHERE term = ’18S’
GROUP BY subject
ORDER BY enrollments desc
A list of the subjects offered in Spring 2018 with count of enrollments, in descending order…

17. Little Aggregated Reports
SELECT subject,
COUNT(subject) enrollments
FROM term_enrollment_table
WHERE term = ’18S’
GROUP BY subject
ORDER BY enrollments desc
Subject | Enrollments
Chem
Math
English 2011
Psych
. . .

18. Coding New Columns SELECT
CASE WHEN subject in (‘Math’,’Chem’) THEN ‘STEM’
ELSE ‘Not STEM’
END STEM_flag,
grade
FROM term_enrollment_table
WHERE term = ‘18F’
Grades for Fall 2018 marked as STEM or not STEM…

19. Coding New Columns SELECT
CASE WHEN subject in (‘Math’,’Chem’) THEN ‘STEM’
ELSE ‘Not STEM’
END STEM_flag,
grade
FROM term_enrollment_table
WHERE term = ‘18F’
STEM_Flag | Grade STEM B
STEM A-
STEM C
Not STEM A
Not STEM B+
STEM D
. . .

20. WHEN subject in (‘Math’,’Chem’) THEN ‘STEM’
CASE
WHEN subject in (‘Math’,’Chem’) THEN ‘STEM’
WHEN subject in (‘English’,’Spanish’) THEN ‘HUMANITIES’
ELSE ‘Other’ END discipline_group
The code will test until it finds a match, then return the ‘THEN’ value and go to the next row.
The new column name
appears after the ‘END’.
Subject Discipline_Group
Chem STEM
Spanish HUMANITIES
Math STEM
Psych OTHER
English HUMANITIES

21. Fancier Output for Reports
What if I want something that looks like this:
Subject | Enrollment 16F | Enrollment 17F | Enrollment 18F
Chem
English
Math
Psych
Spanish

22. Fancier Output for Reports
Or something like this:
Term | Subject | A’s Awarded | B’s Awarded | C’s Awarded
17F Chem
17F English
17F Math
17F Psych
17F Spanish

23. Fancier Output for Reports
I’d have to create a new column
…and aggregate at the same time.
A CASE statement, plus a GROUP BY… ???

24. Term Trend of Total Course Enrollment per Subject
SELECT subject,
SUM(CASE WHEN term = ‘16F’ then 1 else 0 end) enrollment_16F,
SUM(CASE WHEN term = ‘17F’ then 1 else 0 end) enrollment_17F,
SUM(CASE WHEN term = ‘18F’ then 1 else 0 end) enrollment_18F
FROM term_enrollment_table
GROUP BY subject
ORDER BY subject
Subject | Enrollment_16F | Enrollment_17F | Enrollment_18F
Chem
English
Math
Psych
Spanish

25. Grade Counts per Subject in a Term
SELECT term, subject,
SUM(CASE WHEN grade in (‘A+’,‘A’,’A-’) then 1 else 0 end) As,
SUM(CASE WHEN grade in (‘B+’,‘B’,’B-’) then 1 else 0 end) Bs,
SUM(CASE WHEN grade in (‘C+’,’C’,’C-’) then 1 else 0 end) Cs
FROM term_enrollment_table
WHERE term = ’17F’
GROUP BY term, subject
ORDER BY term, subject
Term | Subject | A’s | B’s | C’s
17F Chem
17F English
17F Math
17F Psych
17F Spanish

26. Learning Outcomes Know what SQL is Read a basic SQL SELECT statement
Find online opportunities to learn the language
Recognize examples of SQL syntax and identify what they do
Consider how the results from a SELECT statement can be formatted to meet your needs

27. Things You Need to Do with Data?

28. Kelly Wahl UCLA kwahl@college.ucla.edu
Happy SQLing!
Kelly Wahl
UCLA