使用 case 语句从 SELECT 更新记录。 (mysql)答案

【问题标题】：UPDATE records from SELECT using a case statement. (mysql)使用 case 语句从 SELECT 更新记录。 (mysql)
【发布时间】：2019-03-17 11:04:01
【问题描述】：

我正在尝试使用 case 语句更新记录集合，但我得到：

错误：#1064 - 您的 SQL 语法有错误；检查手册对应于您的 MySQL 服务器版本以获得正确的语法在'FROM(SELECT SoftwareProjects.id, SoftwareProjects.Project_Code，Description' 在第 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)

【问题讨论】：

标签： mysql sql join sql-update case

【解决方案1】：

试试下面

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

【讨论】：

感谢您的回复，我现在收到“#1052 - 字段列表中的 'HoursEstimated' 列不明确”
@cyberghost47，修改了你现在可以查看的答案