一、修改前
select year,month,sum(ysl)ysl1,sum(isnull(ysl_sy_dx,0))ysl2,sum(isnull(actual_consume_total,0)) as ysl1_1,(sum(isnull(actual_consume_groundwater,0))) as ysl2_1
from(select re.xian_cd,year,month,sum(isnull(ysl,0)) ysl,sum(isnull(ysl_sy_dx,0))ysl_sy_dx, cast((cast(sum(isnull(ysl,0)) as decimal(18,6)) / 10000) as decimal(18,6)) as actual_consume_total,cast((cast(sum(isnull(ysl_sy_dx,0)) as decimal(18,6)) / 10000) as decimal(18,6)) as actual_consume_groundwaterfrom testgroup by xian_cd,year,month
)a
where year = 2023 and month = 2
group by year,month
order by year,month;
运行结果:
year | month | ysl1(立方米) | ysl2(立方米) | ysl1_1(万立方米) | ysl2_1(万立方米) |
2023 | 2 | 7464174.287 | 2423411.559 | 746.417352 | 242.341079 |
二、修改后
select year,month,sum(ysl)ysl1,sum(isnull(ysl_sy_dx,0))ysl2,sum(isnull(actual_consume_total,0)) as ysl1_1,(sum(isnull(actual_consume_groundwater,0))) as ysl2_1
from(select re.xian_cd,year,month,sum(isnull(ysl,0)) ysl,sum(isnull(ysl_sy_dx,0))ysl_sy_dx, cast((cast(sum(isnull(ysl,0)) as decimal(18,6)) / 10000.0) as decimal(18,6)) as actual_consume_total,cast((cast(sum(isnull(ysl_sy_dx,0)) as decimal(18,6)) / 10000.0) as decimal(18,6)) as actual_consume_groundwaterfrom testgroup by xian_cd,year,month
)a
where year = 2023 and month = 2
group by year,month
order by year,month;
运行结果:
year | month | ysl1(立方米) | ysl2(立方米) | ysl1_1(万立方米) | ysl2_1(万立方米) |
2023 | 2 | 7864174.287 | 4423411.559 | 786.41742870 | 442.34115590 |
三、总结
从上面可以看出,ysl1和ysl1_1、ysl2和ysl2_1的整数部分是一样的,有区别的是小数位(转成万m³后要保留4位小数),第一种方法的差别比较大,第二种换算后就一样了
区别有两点:
①cast(sum(isnull(ysl_sy_dx,0)) as decimal(18,6)),sum()之后县转换成decimal
②/10000改成/10000.0