sql - EXCEPT 子句的访问替代

Question

如何在 ms 访问中获得与下面的 SQL 代码相同的结果？它不承认该EXCEPT子句...

SELECT DISTINCT 
       P.Name, 
       T.Training
  FROM Prof AS P, 
       Training_done AS TC, 
       Trainings AS T
 WHERE (P.Name Like '*' & NameProf & '*') 
   AND (P.Primary_Area = T.Cod_Area)
EXCEPT
SELECT DISTINCT 
       P.Name, 
       T.Training
  FROM Prof AS P, 
       Training_done AS TC, 
       Trainings AS T
 WHERE (P.Name Like '*' & NameProf & '*') 
   AND (P.Cod_Prof = TC.Cod_Prof);

提前致谢！

Answer 1

为了摆脱EXCEPT你可以结合条件并否定第二个：

SELECT DISTINCT 
       P.Name, 
       T.Training
  FROM Prof AS P, 
       Training_done AS TC, 
       Trainings AS T
 WHERE ((P.Name Like '*' & NameProf & '*') AND
        (P.Primary_Area = T.Cod_Area)) 
   AND NOT ((P.Name Like '*' & NameProf & '*') AND
            (P.Cod_Prof = TC.Cod_Prof));

Answer 2

SELECT A.x FROM A
EXCEPT
SELECT B.x FROM B

对应于

SELECT A.x FROM A 
LEFT JOIN B 
ON A.x = B.x 
WHERE B.x IS NULL

Answer 3

使用MS Access > Create > Query Wizard中的find unmatched 向导，您将得到以下结果

联合是一个单独的访问查询，我用来联合几个表而不是使用子查询

SELECT TableMain.Field1
FROM TableMain LEFT JOIN [Union] ON TableMain.[Field1] = Union.[field1]
WHERE (((Union.field1) Is Null));

Answer 4

这里不是一个明确的例子，但考虑对两个获取的表进行 UNION 并从该联合中选择具有少于 2 个特定字段组合实例的对。这意味着，如果每个表在字段组合上具有多个具有相同值的记录实例，则这些记录是相同的并且可以从结果集中消除。如果不是，它们对一个表是唯一的，只留下所选表中与另一表不匹配的记录。有点像穷人的“除了”KW。