bigquery sum函数正在返回（-0.0）处理float数据类型。真的很惊讶看到负零。它只在对float数据类型应用window函数时发生，如下所示。

select sum(x) over (partition by test) from (SELECT x,test FROM UNNEST([-5.5,5.5]) AS x, UNNEST(['ab','ab']) as test);    **--returns -0.0**

但对于整型数据，它的计算是很好的。

select sum(x) over (partition by test) from (SELECT x,test FROM UNNEST([-5,5]) AS x, UNNEST(['ab','ab']) as test);   **--returns 0.0**

任何想法都将不胜感激。