Access 2013-一对多关系：在“一个”侧显示所有值，仅在“许多”侧选择值

Question

I've got two tables - tblSalaryBand and tblSalaryBandYear linked by tblSalaryBand.ID = tblSalaryBandYear.SalaryBandID . Within tblSalaryBandYear I have values for BandMax and BandMin, and then a ReviewYearID. So for each Salary Band I can have a Max and a Min for each year.

What I would like to do is have a list of all Salary Bands and the Max and Min for the selected year. However there may not yet be a values for the Salary Band for that year in the tblSalaryBandYear .

I've got a continuous form setup which I can get to show all Salary Bands even if they don't have a value in tblSalaryBandYear using an left join:

SELECT tblSalaryBand.BandName, tblSalaryBandYear.BandMax, tblSalaryBandYear.BandMin, tblSalaryBand.ID AS SalaryBandID
FROM tblSalaryBand LEFT JOIN tblSalaryBandYear ON tblSalaryBand.ID = tblSalaryBandYear.SalaryBandID;

But when I try to filter them down by ReviewYearID they don't show at all if no value exists in tblSalaryBandYear .

SELECT tblSalaryBand.BandName, tblSalaryBandYear.BandMax, tblSalaryBandYear.BandMin, tblSalaryBand.ID AS SalaryBandID
FROM tblSalaryBand LEFT JOIN tblSalaryBandYear ON tblSalaryBand.ID = tblSalaryBandYear.SalaryBandID
WHERE (((tblSalaryBandYear.ReviewYearID)=[Forms]![frmHome]![SelectedYear]));

Is there a way to have all Salary Bands show and then only show values for BandMin and Max from the selected review year?

Answer 1

The issue is that the where clause effectively eliminates the rows without any matching ReviewYearID (and makes the join behave like an inner join instead of a left outer join).

Try this instead:

SELECT 
  tblSalaryBand.BandName, tblSalaryBandYear.BandMax, 
  tblSalaryBandYear.BandMin, tblSalaryBand.ID AS SalaryBandID
FROM tblSalaryBand 
LEFT JOIN (
    SELECT * 
    FROM tblSalaryBandYear 
    WHERE ReviewYearID = [Forms]![frmHome]![SelectedYear]
) AS SBY ON tblSalaryBand.ID = SBY.SalaryBandID