第一个（）INNER JOIN

Question

SELECT tblT.Tick, First(tblB.BDF) AS FirstOfBDF
FROM tblT INNER JOIN tblB ON tblT.Tick = tblB.Tick
GROUP BY tblT.Tick;

我的访问表（tblB）按Tick排序，然后由BDF排序。为什么它不能检索到正确的数据呢？

Answer 1

除非您明确提及Order by，否则无法保证对表进行排序。

select top 1  tblT.Tick, First(tblB.BDF) AS FirstOfBDF
 from FROM tblT INNER JOIN tblB ON tblT.Tick = tblB.Tick
    GROUP BY tblT.Tick
    Order by tblt.Tick ;