使用case语句从SELECT更新记录。 （mysql）

Question

我正在尝试使用case语句更新记录集合，但得到：

  

错误：＃1064-您的SQL语法有错误；查看手册   对应于您的MySQL服务器版本的正确语法，   在'FROM（SELECT SoftwareProjects.id，   SoftwareProjects.Project_Code，Description'，位于第8行

这是我的查询

UPDATE SoftwareProjects
SET BudgetStatus =
CASE
WHEN ((HoursBooked/HoursEstimated) * (100/1) < 80) THEN 1
WHEN ((HoursBooked/HoursEstimated) * (100/1) > 81 && (HoursBooked/HoursEstimated) * (100/1) < 100 ) THEN 2
ELSE   3
END
FROM
(SELECT SoftwareProjects.id, SoftwareProjects.Project_Code,  Description,
        BudgetStatus,  TimelineStatus,  QualityStatus,  OverallStatus,
        DeliveryDate,  HoursEstimated,  s4_project_id, 
        SUM( hours_adjusted ) AS HoursBooked
                        FROM SoftwareProjects
                        LEFT JOIN S4Admin.ts_entries ON s4_project_id = 
                        S4Admin.ts_entries.project
                        GROUP BY Description
                        ORDER BY  SoftwareProjects.Description)

Answer 1

尝试以下

UPDATE SoftwareProjects a
  JOIN
  (SELECT SoftwareProjects.id, SoftwareProjects.Project_Code,  Description,  BudgetStatus,  TimelineStatus,  QualityStatus,  OverallStatus,  DeliveryDate,  HoursEstimated,  s4_project_id, SUM( hours_adjusted ) AS HoursBooked
                          FROM SoftwareProjects
                          LEFT JOIN S4Admin.ts_entries ON s4_project_id = 
                          S4Admin.ts_entries.project
                          GROUP BY Description
                          ORDER BY  SoftwareProjects.Description) b on a.id=b.id

SET a.BudgetStatus =
  CASE
  WHEN ((HoursBooked/b.HoursEstimated) * (100/1) < 80) THEN 1
  WHEN ((HoursBooked/b.HoursEstimated) * (100/1) > 81 && (HoursBooked/b.HoursEstimated) * (100/1) < 100 ) THEN 2
  ELSE   3
  END