题解 | 分析客户逾期情况

SELECT
    ct.pay_ability,
    CONCAT(ROUND(SUM(CASE WHEN lt.overdue_days IS NOT NULL THEN 1 ELSE 0 END)/COUNT(*)*100,1),'%') AS overdue_ratio
FROM
    loan_tb lt
JOIN
    customer_tb ct ON lt.customer_id = ct.customer_id
GROUP BY
    ct.pay_ability
ORDER BY
    overdue_ratio DESC

#百分比，小数点，四舍五入

CONCAT(ROUND( ( )*100,1),'%')

#判断，定义

CASE WHEN THEN 1 ELSE 0