访问查询：使用用户输入在sql中选择要查询的列

Question

我是 ACCESS 和 SQL 的新手。如果我误用了某些参考文献和术语，我深表歉意。我正在尝试使用用户输入来选择表中的一个字段，然后根据用户条件过滤该字段中的数据。

我有一个表Emissions_Units 有很多列，我想制作一个漂亮的表格供用户选择污染物（这是我表中的一列），然后选择适用于该污染物的标准（即桌子）。表中污染物或列包括CO_Emissions、NO2_Emissions、PM_Emissions。

然后，一旦选择了列，我想根据用户最大和最小标准过滤该列。然后让查询显示结果。

我包含了一些我一直在处理的 SQL 代码，这些代码不起作用，但可能会显示我正在尝试做的事情。我也试过SWITCH 而不是IIF。如果这是可能的，那么我还想从该表中与查询中的行匹配的其他列中获取信息。例如，我想从与满足用户输入结果的行关联的名称和位置列中提取信息。

PARAMETERS [Enter Pollutant to Review (CO, NO2, PM):] Text, [Enter Maximum Emissions (0.00 g/s):] Number, [Enter Minimum Emissions (0.00 g/s):] Number;

SELECT
    IIF([Enter Pollutant to Review (CO, NO2, PM):] = "CO", Emissions_Units.CO_Emissions AS CalcValues,
    IIF([Enter Pollutant to Review (CO, NO2, PM):] = "NO2", Emissions_Units.NO2_Emissions AS CalcValues,
    IIF([Enter Pollutant to Review (CO, NO2, PM):] = "PM", Emissions_Units.PM_Emissions AS CalcValues, 'Retry' )
  )
)
FROM Emissions_Units
WHERE CalcValues >= [Enter Minimum Emissions (0.00 g/s)] 
  AND CalcValues <= [Enter Maximum Emissions (0.00 g/s)];

Answer 1

此查询有效：

PARAMETERS [Enter Pollutant to Review (CO, NO2, PM):] Text, [Enter Minimum Emissions in gps] Number, [Enter Maximum Emissions in gps] Number;

SELECT *, Switch([Enter Pollutant to Review (CO, NO2, PM):] = "CO", Emissions_Units.CO_Emissions,
  [Enter Pollutant to Review (CO, NO2, PM):] = "NO2", Emissions_Units.NO2_Emissions,
  [Enter Pollutant to Review (CO, NO2, PM):] = "PM", Emissions_Units.PM_Emissions) AS CalcValues
 
FROM Emissions_Units

WHERE Switch([Enter Pollutant to Review (CO, NO2, PM):] = "CO", Emissions_Units.CO_Emissions,
  [Enter Pollutant to Review (CO, NO2, PM):] = "NO2", Emissions_Units.NO2_Emissions,
  [Enter Pollutant to Review (CO, NO2, PM):] = "PM", Emissions_Units.PM_Emissions)

BETWEEN [Enter Minimum Emissions in gps] AND [Enter Maximum Emissions in gps];

PARAMETERS 子句不喜欢 0.00，所以我改写了提示。但是，不是在查询中弹出提示，而是在表单上引用控件以供用户输入。