CREATE TABLE checking (custid VARCHAR2, balance VARCHAR2)
CREATE TABLE accounts (custid VARCHAR2)
CREATE TABLE savings (balance VARCHAR2, custid VARCHAR2)

Find the saving balance of the account with the highest checking balance.
SELECT T3.balance FROM accounts AS T1 JOIN checking AS T2 ON T1.custid = T2.custid JOIN savings AS T3 ON T1.custid = T3.custid ORDER BY T2.balance DESC LIMIT 1
SELECT "T3"."balance" FROM "accounts" "T1" JOIN "checking" "T2" ON "T1"."custid" = "T2"."custid" JOIN "savings" "T3" ON "T1"."custid" = "T3"."custid" ORDER BY "T2"."balance" DESC FETCH FIRST 1 ROWS ONLY