As happy as a sandboy British American informal slang
The word (as) means that It will be alright if the phrase does not have (as). Besides, It can be used 'jolly' instead of 'happy' which still has the same meaning.
when I was a student, I was as happy as a sandboy because I achieved the IELTS scholarship.
David came back with the compliment in the report that he is all smiles and happy as a sandboy.
To become better
People's arms linked together to show the intimacy between two people.
To not wonder, worry or be surprised about what is not predicted will happen in life because anything could happen
American readers are likely to be more intimately familiar with as happy as a clam' that originated in the late nineteenth century in the USA. The Australian version, which originally came there, is as happy as Larry. The phrase was originated from England where the boys could hold on the bucket of sand and their job was to washed off and moved on sand on the steps of buidings in order to they were not slippery. The sand boys might be happy and enjoyed their work.