stddev_samp在创建为视图时更改值

Question

为什么当我按原样选择查询时，它运行良好？所以这是我的查询

SELECT
            AVG(total_score) AS AVGtotal_Score,
            STDDEV_SAMP(total_score) AS STDDEV_SAMPtotal_score,
            AVG(Total_Answer_Time) AS AVGTotal_Answer_Time,
            STDDEV_SAMP(Total_Answer_Time) AS STDDEV_SAMPTotal_Answer_Time,
            AVG(Total_Hint) AS AVGTotal_Hint,
            STDDEV_SAMP(Total_Hint) AS STDDEV_SAMPTotal_Hint,
            AVG(Total_Hint_Time) AS AVGTotal_Hint_Time,
            STDDEV_SAMP(Total_Hint_Time) AS STDDEV_SAMPTotal_Hint_Time
        FROM
            average_pivot

这是输出： z values image

当我尝试将它放在这样的视图中时：

create view ave_temp_z_table as (SELECT
            AVG(total_score) AS AVGtotal_Score,
            STDDEV_SAMP(total_score) AS STDDEV_SAMPtotal_score,
            AVG(Total_Answer_Time) AS AVGTotal_Answer_Time,
            STDDEV_SAMP(Total_Answer_Time) AS STDDEV_SAMPTotal_Answer_Time,
            AVG(Total_Hint) AS AVGTotal_Hint,
            STDDEV_SAMP(Total_Hint) AS STDDEV_SAMPTotal_Hint,
            AVG(Total_Hint_Time) AS AVGTotal_Hint_Time,
            STDDEV_SAMP(Total_Hint_Time) AS STDDEV_SAMPTotal_Hint_Time
        FROM
            average_pivot);

stddev_samp的输出发生了变化..视图的输出是这样的 z values as a view