有主键，同一字段内的几个值进行计算该怎么写

Question

表格是这样的
等级名称 贷款原值 规模占比

规模占比的计算公式是同级别贷款原值/(同类型贷款原值和)
比如正常规模占比=正常贷款原值/(正常贷款原值+关注贷款原值)
这个sql语句怎么写呀？

Answer 1

SELECT
等级，贷款原值 /(贷款原值 + ( SELECT sum(贷款原值) FROM TABLE WHERE 等级 = '正常' or 等级 = '关注' )) AS 规模占比
FROM TABLE
WHERE 等级 = '正常' or 等级 = '关注'
union all
SELECT
等级，贷款原值 /(贷款原值 + ( SELECT sum(贷款原值) FROM TABLE WHERE 等级 = '次级' or 等级 = '可疑' or 等级 = '损失' )) AS 规模占比
FROM TABLE
WHERE 等级 = '次级' or 等级 = '可疑' or 等级 = '损失'