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C20.0046: Database Management Systems Lecture #1 - page 25 / 40

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M.P. Johnson, DBMS, Stern/NYU, Sp2004

25

Querying: Structured Query Language

Find all the students who have taken C20.0046:

SELECT  SSN

FROM Takes

WHERE CID=“C20.0046”

Find all the students who C20.0046 last fall:

SELECT  SSN

FROM Takes

WHERE CID=“C20.0046” AND Semester=“Fall, 2003”

Find the students’ names:

SELECT Name

FROM  Students, Takes

WHERE  Students.SSN=Takes.SSN AND

   CID=“C20.0046” AND Semester=“Fall, 2003”

Query processor does this efficiently.

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