左外部连接3表

Question

我正在更新使用旧外部连接的旧建筑的查询（= *和* =）。我有3个表，我需要包括在一个外部联接。

原来的查询是：

SELECT s.SkillID , 
     NULL AS Signature , 
     NULL AS DPL , 
     CASE WHEN ISNULL(ds.DPL, dg.DPL) IS NULL 
      THEN p.ScaleTo - p.ScaleFrom + 1 
      ELSE ISNULL(ds.DPL, dg.DPL) 
     END AS DefaultDPL 
FROM tbJobs j , 
     tbSkills s 
     INNER JOIN tbSkillGroups sg ON s.SkillGroupID = sg.SkillGroupID , 
     tbPerfScales p , 
     tbDPLs ds , 
     tbDPLs dg 
WHERE j.JobID = 866 
     AND (ds.LevelID=*j.LevelID 
       AND ds.IDType = 1 
       AND ds.GroupOrSkillID=*s.SkillID 
      ) 
     AND (dg.LevelID=*j.LevelID 
       AND dg.IDType = 0 
       AND dg.GroupOrSkillID=*sg.SkillGroupID 
      ) 
     AND ((s.PerfScaleID IS NOT NULL 
       AND p.PerfScaleID = s.PerfScaleID 
      ) 
       OR (s.PerfScaleID IS NULL 
        AND p.PerfScaleID = sg.PerfScaleID 
       ) 
      ) 

我做：

SELECT s.SkillID , 
     NULL AS Signature , 
     NULL AS DPL , 
     CASE WHEN ISNULL(ds.DPL, dg.DPL) IS NULL 
      THEN p.ScaleTo - p.ScaleFrom + 1 
      ELSE ISNULL(ds.DPL, dg.DPL) 
     END AS DefaultDPL 
FROM tbPerfScales p , 
     tbSkills s 
     INNER JOIN tbSkillGroups sg ON s.SkillGroupID = sg.SkillGroupID , 
     tbJobs j 
     LEFT OUTER JOIN tbDPLs ds ON j.LevelID = ds.LevelID 
            AND s.SkillID = ds.GroupOrSkillID 
     LEFT OUTER JOIN tbDPLs dg ON j.LevelID = dg.LevelID 
            AND sg.SkillGroupID = dg.GroupOrSkillID 
WHERE j.JobID = 866 
     AND ds.IDType = 1 
     AND dg.IDType = 0 
     AND ((s.PerfScaleID IS NOT NULL 
       AND p.PerfScaleID = s.PerfScaleID 
      ) 
       OR (s.PerfScaleID IS NULL 
        AND p.PerfScaleID = sg.PerfScaleID 
       ) 
      ) 

出于某种原因，我得到的错误：

The multi-part identifier "s.SkillID" could not be bound.

我知道是在这部分：

tbJobs j 
    LEFT OUTER JOIN tbDPLs ds ON j.LevelID = ds.LevelID 
           AND s.SkillID = ds.GroupOrSkillID 

我不知道我在做什么错。

感谢任何帮助。 何塞

Answer 1

有声明

INNER JOIN tbSkillGroups sg ON s.SkillGroupID = sg.SkillGroupID , 

后逗号这是因为你之后有tbJobs，当它应该是其他表所示。我建议使用CROSS JOIN而不是在FROM子句中使用多个表，因为它会更清晰。

下面是应该工作的查询的基本重写，尽管您应该能够轻松地摆脱大部分交叉连接。

SELECT s.SkillID , 
     NULL AS Signature , 
     NULL AS DPL , 
     CASE WHEN ISNULL(ds.DPL, dg.DPL) IS NULL 
      THEN p.ScaleTo - p.ScaleFrom + 1 
      ELSE ISNULL(ds.DPL, dg.DPL) 
     END AS DefaultDPL 
FROM tbPerfScales p 
     CROSS JOIN tbSkills s 
     CROSS JOIN tbJobs j 
     INNER JOIN tbSkillGroups sg ON s.SkillGroupID = sg.SkillGroupID 
     LEFT OUTER JOIN tbDPLs ds ON j.LevelID = ds.LevelID 
            AND s.SkillID = ds.GroupOrSkillID 
     LEFT OUTER JOIN tbDPLs dg ON j.LevelID = dg.LevelID 
            AND sg.SkillGroupID = dg.GroupOrSkillID 
WHERE j.JobID = 866 
     AND ds.IDType = 1 
     AND dg.IDType = 0 
     AND ((s.PerfScaleID IS NOT NULL 
       AND p.PerfScaleID = s.PerfScaleID 
      ) 
       OR (s.PerfScaleID IS NULL 
        AND p.PerfScaleID = sg.PerfScaleID 
       ) 
      ) 

Answer 2

您不能混用不同的SQL语法。如果你打算使用ANSI-92，你需要纠正所有连接，而不仅仅是外部连接。一致性是关键。

现在，逗号是不正确的语法。你需要为每个表添加一个连接，或者将每个表的连接拉出来，交给达伦的答案。 这是问题：

FROM tbPerfScales p , 
     tbSkills s 
     INNER JOIN tbSkillGroups sg ON s.SkillGroupID = sg.SkillGroupID , 
     tbJobs j 
     LEFT OUTER JOIN tbDPLs ds ON j.LevelID = ds.LevelID 
            AND s.SkillID = ds.GroupOrSkillID 
     LEFT OUTER JOIN tbDPLs dg ON j.LevelID = dg.LevelID 
            AND sg.SkillGroupID = dg.GroupOrSkillID 

它需要的线沿线：

FROM tbPerfScales p 
    INNER JOIN tbSkills s ON p.<field> = s.<field> 
     INNER JOIN tbSkillGroups sg ON s.SkillGroupID = sg.SkillGroupID 
     INNER JOIN tbJobs j on j.<field> = <table p? sg? not sure>.<field> 
     LEFT OUTER JOIN tbDPLs ds ON j.LevelID = ds.LevelID 
            AND s.SkillID = ds.GroupOrSkillID 
     LEFT OUTER JOIN tbDPLs dg ON j.LevelID = dg.LevelID 
            AND sg.SkillGroupID = dg.GroupOrSkillID