Question

我正在研究MySQL数据库。我有一个表empreporting，此表包含 employeeid和reportingemployeeid列

SELECT e3.`ReportingEmployeeId` AS Level0,e2.`ReportingEmployeeId` AS Level1,e1.`ReportingEmployeeId` AS Level2,e1.`EmployeeId` AS Level3
FROM empreporting e1
LEFT JOIN empreporting e2 ON e1.`ReportingEmployeeId` = e2.`EmployeeId`
LEFT JOIN empreporting e3 ON e2.`ReportingEmployeeId` = e3.`EmployeeId`

以上查询给出以下结果：

Level0  Level1  Level2  Level3

\N      \N      379      369

\N      379     484      372

\N      \N      \N       379

所需的结果格式为：

Level0  Level1  Level2  Level3

379      369     \N      \N

379      484     372     \N

379      \N      \N      \N

请任何人帮助我。提前致谢

普拉卡什

Answer 1

最后写的查询

SELECT 
CASE 
    WHEN e3.`ReportingEmployeeId` IS NOT NULL THEN e3.`ReportingEmployeeId`+1000000 
    WHEN e3.`ReportingEmployeeId` IS NULL AND e2.`ReportingEmployeeId` IS NOT NULL THEN e2.`ReportingEmployeeId`
    WHEN e3.`ReportingEmployeeId` IS NULL AND e2.`ReportingEmployeeId` IS NULL AND e1.`ReportingEmployeeId` IS NOT NULL THEN e1.`ReportingEmployeeId`
    WHEN e3.`ReportingEmployeeId` IS NULL AND e2.`ReportingEmployeeId` IS NULL AND e1.`ReportingEmployeeId` IS NULL AND e1.`EmployeeId`  IS NOT NULL THEN e1.`EmployeeId` 
END AS Level0,
CASE 
    WHEN e3.`ReportingEmployeeId` IS NOT NULL THEN e2.`ReportingEmployeeId`
    WHEN e3.`ReportingEmployeeId` IS NULL AND e2.`ReportingEmployeeId` IS NOT NULL THEN e1.`ReportingEmployeeId`
    WHEN e3.`ReportingEmployeeId` IS NULL AND e2.`ReportingEmployeeId` IS NULL AND e1.`ReportingEmployeeId` IS NOT NULL THEN e1.`EmployeeId`
    WHEN e3.`ReportingEmployeeId` IS NULL AND e2.`ReportingEmployeeId` IS NULL AND e1.`ReportingEmployeeId` IS NULL AND e1.`EmployeeId`  IS NOT NULL THEN NULL
END AS Level1,
CASE 
    WHEN e3.`ReportingEmployeeId` IS NOT NULL THEN e1.`ReportingEmployeeId`
    WHEN e3.`ReportingEmployeeId` IS NULL AND e2.`ReportingEmployeeId` IS NOT NULL THEN e1.`EmployeeId` 
    WHEN e3.`ReportingEmployeeId` IS NULL AND e2.`ReportingEmployeeId` IS NULL AND e1.`ReportingEmployeeId` IS NOT NULL THEN NULL
    WHEN e3.`ReportingEmployeeId` IS NULL AND e2.`ReportingEmployeeId` IS NULL AND e1.`ReportingEmployeeId` IS NULL AND e1.`EmployeeId`  IS NOT NULL THEN NULL
END AS Level2,
CASE
    WHEN e3.`ReportingEmployeeId` IS NOT NULL THEN e1.`EmployeeId` 
    WHEN e3.`ReportingEmployeeId` IS NULL AND e2.`ReportingEmployeeId` IS NOT NULL THEN NULL 
    WHEN e3.`ReportingEmployeeId` IS NULL AND e2.`ReportingEmployeeId` IS NULL AND e1.`ReportingEmployeeId` IS NOT NULL THEN NULL
    WHEN e3.`ReportingEmployeeId` IS NULL AND e2.`ReportingEmployeeId` IS NULL AND e1.`ReportingEmployeeId` IS NULL AND e1.`EmployeeId`  IS NOT NULL THEN NULL
END AS  Level3
FROM empreporting e1
LEFT JOIN empreporting e2 ON e1.`ReportingEmployeeId` = e2.`EmployeeId` 
LEFT JOIN empreporting e3 ON e2.`ReportingEmployeeId` = e3.`EmployeeId`

Answer 2

试

SELECT e1.EmployeeId AS Level0,e2.`EmployeeId` AS Level1,e3.`EmployeeId` AS Level2,e3.`ReportingEmployeeId` AS Level3
FROM empreporting e1
LEFT JOIN empreporting e2 ON e1.`ReportingEmployeeId` = e2.`EmployeeId`
LEFT JOIN empreporting e3 ON e2.`ReportingEmployeeId` = e3.`EmployeeId`

不是在mysql中向左移动的列

2 个答案: