MS Access SQL：添加两个COUNT语句将返回多个副本而不是一个

Question

所以我试图在两个不同的COUNTS之间执行基本的算术函数（+， - ，*，/）。在测试运行中，我一直在查询以使用以下语句返回我的两个计数（“724”）的总和：

SELECT (SELECT COUNT(qryAttainment.[Attainment Samples Received]) 
          FROM qryAttainment 
          WHERE qryAttainment.[Attainment Samples Received]="On Time") +
       (SELECT COUNT(qryAttainment.[Attainment CofA Issued]) 
          FROM qryAttainment 
         WHERE qryAttainment.[Attainment CofA Issued]="On Time") AS [Test] 
  FROM qryAttainment

不幸的是，它返回了1240行，所有行都填充了相同的数字（“724”）。如何让它只返回一行所需的答案？

Answer 1

SELECT 
    SUM(IIF(qryAttainment.[Attainment Samples Received]="On Time", 1, 0)) 
    +
    SUM(IIF(qryAttainment.[Attainment CofA Issued]="On Time", 1,  0))
 FROM qryAttainment