Hi @Anonyamann,
It looks like you've had a leg snap off one of the Fountain Products 697 x 425 x 655mm Raised Garden Beds.
You could use this Selleys 3ml Power Grip All Plastics Glue to glue it back together, however, you would need to be careful when moving it in the future as there will now always be a weakness.
If you are concerned with this, it may be time for a replacement.
Let me know if you require any further assistance.
Jacob
