Why pressure exerted by the solid and fluid are different?

Solids exert pressure because of their weight, i.e. pull of mass by the centre of the Earth with an acceleration of g = 9.8 ${{ms}^{-2}}$ and acts downwards towards the centre of the Earth. Similarly, fluids, i.e. gases and liquids both exert equal pressure in all directions over the innerwalls of the container in which it is kept.