What is the purpose of the SQL "GROUP BY"

Statements:

Some bats are balls

All balls are stumps  

Conclusions:

I. Some stumps are bats

Statements: Some doors are windows.

All houses are windows.

No mirror is a door.

Conclusions: I. Some doors are mirror

Statements: All watches are clocks.

Some wall clocks are calculators.

Conclusions: I. No watch is a calculator.

Statement: 

All Chairs are Sofa.

All bookshelf are Sofa.

All Beds are Chairs.

All cabinet are Sofas.

Statements:

Some laptops are printer.

All printer are camera.

Some camera are scanner.

Conclusions:

Statements-

1. All phones are wires.

2. All switches are wires.

3. Some wires are poles.

4. Some poles are not phones.

Statements:

All hotels are buses.

Some buses are cars.

All cars are trams.

Some trams are clouds.

Conclusions:

Statements:

Some label is brand.

All brand is price.

No price is promotion.

Every promotion is package.

Statements:

Some authors are teachers.

All teachers are poets.

Some poets are artists.

Conclusions: