Build a loan repayment progress report. CTE 1: compute total_paid (sum of amount from payments) per loan. CTE 2: join to loans for loan details. Main query: return loan_id, loan_type, principal, total_paid, remaining (principal - total_paid), and progress_pct (total_paid / principal * 100 rounded to 1 decimal). Include loans with no payments. Sort by progress_pct descending.