Selection & Projection

1. Selection :::: (cutting down table by records)

2. Projection :::: (cutting down table by columns)

SELECTION ::::: (this is also indicated by 'Sigma')

Using the above Example ('student' table)::

Will select all the rows(records) from the table

> Select * from student where marks > 96 ;

Will show the below table :::

TABLE

Select operation is used for conditions.

PROJECTION :::::::: (this is also also indicated by 'Pie')

If want to display the name column

> Select name from student ;

Will list the entire name column ,

TABLE

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When we use Selection & Projection together.

>Select name from student where marks > 95 ;

TABLE

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