Sports day and weddings are two very different events.
Sports Day is an event where you can't get near the contestants/competitors, you have to be "belakang tali". Therefore you'll a 70-200mm zoom as the best lens for that.
Wedding is an occasion where you can get very close to the 'action' so you'll need a 24-70mm or a zoom lens of that range. And of course a flash that's permanently mounted on the camera!