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Question
What is the difference between the Select and Project commands?
Distinguish Between
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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 |
|
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