Find Duplicate Transactions
A single transaction can only belong to a single block. However, in earlier versions of bitcoin (due to a different database),there was a transaction that was added to two blocks. This transaction can be discovered using this query:
select * from (select transaction_id, count(transaction_id) as duplicates from `bigquery-public-data.bitcoin_blockchain.transactions` group by transaction_id) where duplicates > 1
Find wallets with over 1,000 btc
Find Transactions which transferred over 1000 BTC