Question

我正在尝试编写一个SQL查询，它返回每个员工测试得分的最大值，每个测试都在自己的列中。
到目前为止，我想出了：

SELECT E.id, 
       Concat(E.firstname, ' ', E.middlename, ' ', E.lastname) AS FullName, 
       score1.maxscore, 
       score2.maxscore 
FROM   employees AS E, 
       (SELECT empid, 
               Max(Cast(score AS DECIMAL)) AS MaxScore 
        FROM   filledsoc 
        WHERE  socid = '87bf5fba-5702-4304-869c-8707956d34d0' 
        GROUP  BY empid) AS score1, 
       (SELECT empid, 
               Max(Cast(score AS DECIMAL)) AS MaxScore 
        FROM   filledsoc 
        WHERE  socid = '340363d9-e9a2-478b-b819-d3a56d337561' 
        GROUP  BY empid) AS score2 
WHERE  E.id = score1.empid 
       AND E.id = score2.empid

这只是一个testquery，最终的查询将动态构建。我的问题是查询只返回所有列都有值的结果。
如果其中一个subquerys返回空，则全部跳过该员工。
我需要的是一个返回表'employees'中所有行的查询，只有当它存在时才填充score1.maxscore和score2.maxscore。如果它不是'0'或没有什么会好的......

对此有任何帮助将不胜感激。

米歇尔

Answer 1

SELECT E.ID, CONCAT(E.FirstName, ' ', E.MiddleName, ' ', E.LastName) AS FullName, 
(
  SELECT MAX(CAST(F1.Score AS DECIMAL))
  FROM FilledSOC AS F1
  WHERE F1.SocID = '87bf5fba-5702-4304-869c-8707956d34d0' 
  AND E.ID = F1.EmpID
) AS Score_1,
(
  SELECT MAX(CAST(F2.Score AS DECIMAL))
  FROM FilledSOC AS F2
  WHERE F2.SocID = '340363d9-e9a2-478b-b819-d3a56d337561' 
  AND E.ID = F2.EmpID
) AS Score_2
FROM Employees AS E

带子查询的查询需要从原始查询返回所有行（即使子查询返回空）

1 个答案: