Tell me claim 621's claim amount.
select amount_claimed from claims where claim_id = 621
How about its settlement claim amount?
select t2.amount_claimed from claims as t1 join settlements as t2 on t1.claim_id = t2.claim_id where t1.claim_id = 621
How many settlements does each claim correspond to? List the claim id and the number of settlements.
select t1.claim_id, count(*) from claims as t1 join settlements as t2 on t1.claim_id = t2.claim_id group by t1.claim_id