查询MySQL数据库

有人能帮我在这个查询中添加第三个包含疾病风险因素的表吗。这张桌子是tblRiskFactors

SELECT tblDiseases.disease
FROM tblRel 
   LEFT JOIN tblDiseases ON tblRel.diseaseID = tblDiseases.diseaseID
WHERE tblRel.symptomID = '1' AND tblRel.symptomID = '2' AND tblRel.symptomID ='3'

要进一步了解加入的更多信息，请访问以下链接：

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你能给出表格的结构吗？你真的需要给我们更多的信息。您能提供这三个表的结构以及您希望如何连接它们吗？

SELECT  tblDiseases.disease
FROM    tblRel 
        LEFT JOIN tblDiseases 
            ON tblRel.diseaseID = tblDiseases.diseaseID
        LEFT JOIN tblRiskFactors
            ON -- define the linking condition here
WHERE   tblRel.symptomID = '1' AND 
        tblRel.symptomID = '2' AND 
        tblRel.symptomID = '3'

SELECT tblDiseases.disease as disease 
FROM tblRel 
   LEFT JOIN tblDiseases ON tblRel.diseaseID = tblDiseases.diseaseID
   LEFT JOIN tblRiskFactors ON tblRel.relation_column = tblRiskFactors.relation_column
WHERE tblRel.symptomID in (1,2,3)