如何有效地使用 min() 和 max()？

Question

我有一个 sql 查询，我检查一个值是否在表的最大值和最小值之间。我现在实现如下：

SELECT spectrum_id, feature_table_id
FROM 'spectrum', 'feature' 
WHERE `spectrum`.msrun_msrun_id = 1
AND `feature`.msrun_msrun_id = 1
AND (SELECT min(rt) FROM `convexhull` WHERE `convexhull`.feature_feature_table_id =  `feature`.feature_table_id) <= scan_start_time 
AND scan_start_time <= (SELECT max(rt) FROM `convexhull` WHERE 'convexhull'.feature_feature_table_id = 'feature'.feature_table_id)
AND (SELECT min(mz) FROM `convexhull` WHERE `convexhull`.feature_feature_table_id = `feature`.feature_table_id) <= base_peak_mz 
AND base_peak_mz <= (SELECT max(mz) FROM `convexhull` WHERE `convexhull`.feature_feature_table_id = `feature`feature_table_id)

这运行非常缓慢，因为每次运行此查询时我都会从凸包中选择 4 次，所以我尝试使用内部连接对其进行改进：

SELECT spectrum_id, feature_table_id 
FROM 'spectrum', 'feature'
INNER JOIN `convexhull` ON `convexhull`.feature_feature_table_id = `feature`.feature_table_id
WHERE `spectrum`.msrun_msrun_id = ? "+ 
AND `feature`.msrun_msrun_id = ? "+
AND min(`convexhull`.rt) <= scan_start_time "+
AND scan_start_time <= max(`convexhull`.rt) "+
AND min(`convexhull`.mz) <= base_peak_mz "+
AND base_peak_mz <= max(`convexhull`.mz)", spectrumFeature_InputValues)

但是，min() 和 max() 语句只能在 select 语句之后使用。如何让第一次查询更有效率，这样我就可以得到最小和最大 rt 和 mz 而不必进行 4 次查询？

Answer 1

编辑：又过了几分钟，又看了一遍，发现所有数据都来自那个表，所以这样的东西应该可以工作

SELECT 
    spectrum_id
    ,feature_table_id
FROM 
    spectrum AS s
    INNER JOIN feature AS f
        on f.msrun_msrun_id = s.msrun_msrun_id
    INNER JOIN (select 
         feature_feature_table_id
         ,min(rt) AS rtMin
        ,max(rt) AS rtMax
        ,min(mz) AS mzMin
        ,max(mz) as mzMax
     FROM 
        convexhull
     GROUP BY 
         feature_feature_table_id
     ) AS t
     ON t.feature_feature_table_id = f.feature_table_id
WHERE
    s.msrun_msrun_id = 1
    AND s.scan_start_time >= t.rtMin
    AND s.scan_start_time <= t.rtMax
    AND base_peak_mz >= t.mxMin
    AND base_peak_mz <= t.mzMax

我认为您想从凸包表中进行选择并按 feature_feature_table_id 进行分组，以获得该分组中的最小和最大 rt。

然后，您可以将该选择括在括号中，为其命名（如 t）并加入它。

希望这足以让您上路.. 如果不在这里创建示例架构：http://sqlfiddle.com/

并输入您的查询，我可以修改它。

作为旁注，我认为您希望在特定字段上加入这些表，而不是使用 where 子句比较从两者中进行选择：

SELECT spectrum_id, feature_table_id
FROM 'spectrum', 'feature' 
WHERE `spectrum`.msrun_msrun_id = 1
AND `feature`.msrun_msrun_id = 1

和：

SELECT 
    spectrum_id
    ,feature_table_id
FROM 
    spectrum AS s
    INNER JOIN feature AS f
        on f.msrun_msrun_id = s.msrun_msrun_id
WHERE
    s.msrun_msrun_id = 1

如果我有什么问题，请告诉我。