Question

Access DB中有三个表。

Labs (ID, TestLab)
Standards (ID, Standard, Keywords)
LabStd (ID, LabID, StdID)

实验室有很多标准。在今天之前我需要做的就是将搜索短语与Standards表中的关键字或标准列相匹配。

Select Labs.ID, Labs.TestLab, Standards.standard
FROM Standards INNER JOIN (Labs INNER JOIN LabStd 
    ON Labs.ID = LabStd.LabID)
  ON Standards.ID = LabStd.StdID 
WHERE Standards.Keywords LIKE "%labstandard%"
OR Standards.standard LIKE "%labstandard%"
ORDER BY Labs.id, Standards.ID

现在，如果在搜索中使用加号（labstandard1 + labstandard2），我需要拆分字符串，看看实验室是否符合搜索中的所有标准。我想我需要使用子查询并试图使用多个WHERE IN语句，但这不起作用，所以我不知所措。

作为测试，我删除了LIKE语句，然后转到了等号。即使每个查询都有匹配的标准，并且与两个标准相关联的实验室，以下查询也不会返回结果。

SELECT Labs.ID, Labs.TestLab, Standards.standard
FROM Standards INNER JOIN (Labs INNER JOIN LabStd 
    ON Labs.ID = LabStd.LabID) 
ON Standards.ID = LabStd.StdID 
WHERE LabStd.StdID IN 
    (SELECT ID AS StdID FROM Standards 
     WHERE (Standards.Keywords = 'labstandard1' 
     OR Standards.standard ='labstandard1')
    ) 
AND LabStd.StdID IN 
    (SELECT ID as StdID 
     FROM Standards
     WHERE (Standards.Keywords = 'labstandard2'
            OR Standards.standard ='labstandard2')
    ) 
ORDER BY Labs.id, Standards.ID

我希望我解释得那么清楚，如果我需要澄清任何事情，请告诉我。

Answer 1

像这样的东西可能是，认为标准。关键词表明这应该是... ...

Select ID as StdID From Standards Where 
Standards.Keywords ='labstandard1' 
OR 
Standards.standard = "labstandard1"
OR
Standards.Keywords ='labstandard2' 
OR 
Standards.standard = "labstandard2"

然后使用All获取labstds

select LabStd.LabID 
Where StdId = all (Select ID as StdID From Standards Where 
Standards.Keywords ='labstandard1' 
OR 
Standards.standard = "labstandard1"
OR
Standards.Keywords ='labstandard2' 
OR 
Standards.standard = "labstandard2")

然后加入实验室。

这样的查询可以驱使你疯狂。始终将它们从内到外分开并确认零件。

Answer 2

您上次查询的问题在于您正在寻找单个LabStd行，其中StdId位于两个子集中，这是不可能的。你想要的是找到两个标准都存在的所有实验室。有点像这样：

SELECT 
    *
FROM
    Labs
WHERE
    EXISTS (
        SELECT
            1
        FROM
            LabStd INNER JOIN Standards ON LabStd.StdId = Standards.Id
        WHERE
            LabStd.LabId = Labs.Id
            AND
            ( Standards.Standard = 'labstandard1' or Standards.Keywords = 'labstandard1' )
    )
    AND
    EXISTS (
        SELECT
            1
        FROM
            LabStd INNER JOIN Standards ON LabStd.StdId = Standards.Id
        WHERE
            LabStd.LabId = Labs.Id
            AND
            ( Standards.Standard = 'labstandard2' or Standards.Keywords = 'labstandard2' )
    )

Answer 3

我找到了一个解决方案虽然它很难看。首先是一些数据。

**Standards**
ID      Standard        Keywords    
20      AAMA 505        Dry Shrinkage Thermal Cycling   
26      AAMA 614        High Perf. Organic Coatings on Plastic

**Labs**
ID      TestLab
10      TESTING, INC
21      LABORATORIES, INC.
3       FRESNO TESTING, INC.

**LabStd**
ID      LabID       StdID
283     3           20
284     10          20
285     21          20
291     21          26
299     10          26

这是有效的查询。拉出拉出实验室ID 10和21并省去3，这是正确的。

SELECT Labs.ID, Labs.TestLab, Standards.standard
FROM Standards INNER JOIN (Labs INNER JOIN LabStd 
    ON Labs.ID = LabStd.LabID) 
ON Standards.ID = LabStd.StdID 
WHERE LabStd.StdID IN 
    (
        SELECT labs.testlab 
        FROM Standards INNER JOIN 
            (Labs INNER JOIN LabStd ON Labs.ID = LabStd.LabID) 
        ON Standards.ID = LabStd.StdID 
        WHERE standards.standard = "AAMA 505"
    ) 
AND Labs.TestLab IN 
    (
        SELECT labs.testlab 
        FROM Standards INNER JOIN 
            (Labs INNER JOIN LabStd ON Labs.ID = LabStd.LabID) 
        ON Standards.ID = LabStd.StdID 
        WHERE standards.standard = "AAMA 614"
    ) 
ORDER BY Labs.id, Standards.ID

Answer 4

另一种方法是使用派生表来计算匹配标准的数量。然后使用HAVING子句确保正确的匹配数。

注意：count(*) = 2是唯一搜索字词的数量

SELECT  Labs.ID, Labs.TestLab, Standards.Standard
FROM  (  
          ( Labs INNER JOIN LabStd  ON Labs.ID = LabStd.LabID )
                 INNER JOIN Standards ON Standards.ID = LabStd.StdID )
                 INNER JOIN (
                        SELECT   ls.LabID, COUNT(*) AS NumMatched
                        FROM     Standards s INNER JOIN LabStd ls ON s.ID = ls.StdID
                        WHERE  ( s.standard LIKE "%AAMA 505%" OR s.Keywords LIKE "%AAMA 505%")
                        OR     ( s.standard LIKE "%AAMA 614%" OR s.Keywords LIKE "%AAMA 614%" )
                        GROUP BY ls.LabID
                        HAVING COUNT(*) = 2 
                  )  matched ON matched.LabID = Labs.ID

搜索查询中的多个Where Ins？

4 个答案: