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Tamil Nadu Board of Secondary EducationHSC Science Class 12

What is the difference between the Select and Project commands? - Computer Science

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Question

What is the difference between the Select and Project commands?

Distinguish Between

Solution

Select Project
The SELECT operation(o) is used for selecting a subset with tuples according to a given selection condition. The projection method(n) eliminates all attributes of the input relation but those mentioned in the projection list.
The SELECT operation (o) selects filters out all tuples that do not satisfy the condition. The projection method defines a relation that contains a vertical subset of Relation.
Symbol: σ Symbol: π
General Form:
σ (R)
c
Example:
σ = “Big Data” (STUDENT) course
Example:
π (STUDENT)
course
shaalaa.com
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Chapter 11: Database Concepts - Evaluation [Page 204]

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Samacheer Kalvi Computer Science [English] Class 12 TN Board
Chapter 11 Database Concepts
Evaluation | Q 1. | Page 204
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