09_SELECT.pdf - CITS1402 Relational Database Management...

CITS1402
Relational Database Management Systems
Video 09 — SELECT
Gordon Royle
Department of Mathematics & Statistics

More properties of
SELECT
Today’s lecture explores the
SELECT
statement in more detail
Recall the basic structure:
I
SELECT
Chooses which columns are to be returned by the query
I
FROM
Constructs the initial table to pass to
WHERE
I
WHERE
Selects the rows that are to be passed to
SELECT

Which students are doing CITS1402?
Make a list of names of this year’s CITS1402 students.

Make a plan
I
We need to use Student and Enrolment
The names are in Student and the enrolment details in Enrolment
I
Join the tables based on student number
Need to throw out rows where the student data and enrolment data
are about different students
I
Keep only rows about students in CITS1402 in 2020.
Other rows are irrelevant to this question
I
Choose just the names of these students
Question only asked for a list of names