Let us now talk about the relational operations:

SELECT

The select operation is used to select few specific record from the database based on different criteria, This is a unary operation mathematically denoted as σ

Syntax:

σ  (Relation)

The Boolean expression is specified in is made of a number of clauses of the form:

or

Comparison operators in the set { ≤, ≥, ≠, =, <, <} apply to the attributes whose domains are ordered value like as integer.

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