Mysql group_concat與眾不同，其中給出奇怪的結果

Question

我有下面的查詢工作正常（請參閱下文）。

但是，當我添加條件時，例如AND (specialtyName = '...') ，主要結果很好，但是GROUP_CONCAT僅顯示與條件匹配的結果。

誰能幫我這個忙嗎？

提前致謝。

弗雷德

SELECT 

    tblJobs.jobID, 
    tblJobs.jobName, 
    DATE_FORMAT(tblJobs.jobDate,'%d-%m-%Y'), 

    tblCompanies.companyID, 
    tblCompanies.companyName, 
    tblCompanies.companyNameConvert, 

    GROUP_CONCAT(DISTINCT tblSpecialties.specialtyName 
        ORDER BY FIELD (
            specialtyName, 
            'specialtyName1', 
            'specialtyName2', 
            'specialtyName3'), 
            specialtyName ASC) 
        AS specialtyNames, 

    GROUP_CONCAT(DISTINCT tblSpecialties.specialtyNameConvert 
        ORDER BY FIELD (
            specialtyName, 
            'specialtyName1', 
            'specialtyName2', 
            'specialtyName3'), 
            specialtyName ASC) 
        AS specialtyNamesConvert, 

    GROUP_CONCAT(DISTINCT tblRegions.regionName), 
    GROUP_CONCAT(DISTINCT tblRegions.regionNameConvert) 

FROM tblJobs 

LEFT JOIN tblCompanies ON 
(tblJobs.jobCompany = tblCompanies.companyID) 

LEFT JOIN tblSpecialties ON 
FIND_IN_SET(tblSpecialties.specialtyID, REPLACE(tblJobs.jobSpecialty,' ',',')) 

LEFT JOIN tblRegions ON 
FIND_IN_SET(tblRegions.regionID, REPLACE(tblJobs.jobRegion,' ',','))

WHERE 

    AND jobActive = '1' 
    AND jobDate >= '2013-01-01' 
    AND companyActive = '1' 

GROUP BY jobID 
ORDER BY jobDate DESC, jobID DESC, jobCompany DESC

Answer 1

我想為表和子查詢使用別名可以解決您的問題。 您可以嘗試如下操作：

SELECT 

tblJobs.jobID, 
tblJobs.jobName, 
DATE_FORMAT(tblJobs.jobDate,'%d-%m-%Y'), 

tblCompanies.companyID, 
tblCompanies.companyName, 
tblCompanies.companyNameConvert,  
(SELECT GROUP_CONCAT(DISTINCT ts.specialtyName 
        ORDER BY FIELD (
            specialtyName, 
            'specialtyName1', 
            'specialtyName2', 
            'specialtyName3'), 
            specialtyName ASC) 
        FROM tblSpecialties ts) AS specialtyNames , 
, ... ,
FROM tblJobs 

LEFT JOIN tblCompanies ON 
(tblJobs.jobCompany = tblCompanies.companyID) 

LEFT JOIN tblSpecialties ON 
FIND_IN_SET(tblSpecialties.specialtyID, REPLACE(tblJobs.jobSpecialty,' ',',')) 

LEFT JOIN tblRegions ON 
FIND_IN_SET(tblRegions.regionID, REPLACE(tblJobs.jobRegion,' ',','))

WHERE 

    AND jobActive = '1' 
    AND jobDate >= '2013-01-01' 
    AND companyActive = '1' 

GROUP BY jobID 
ORDER BY jobDate DESC, jobID DESC, jobCompany DESC

我沒有測試此代碼，但可以提供幫助。

Answer 2

如果你說：

WHERE jobActive = '1' AND jobDate >= '2013-01-01' AND companyActive = '1' AND
      specialties = XXX

然后，您將只獲得這些專業。 過濾是在聚合之前完成的。 注意：在where子句中包含這樣的條件也會將外部聯接轉換為內部聯接。 您的聯接可能基於正確對齊的外鍵關系，因此內部聯接可能是合適的。

我猜您真正想要的是按具有該專業的人員來過濾工作，但保留所有其他信息。 您要在聚合后進行過濾。 使用having子句代替where子句來做到這一點：

having sum(specialties = XXX) > 0;

這將僅保留具有特定專業的行，並保留所有其他信息。