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.