Question

我的代码

我有一个Access查询：

SELECT DISTINCT [Request-Priority, ALL_Q].RequestID, "Awaiting Approval" AS RequestStatus
FROM [Request-Priority, ALL_Q] LEFT JOIN LIST_RequestBurndown_Q ON [Request-Priority, ALL_Q].RequestID = LIST_RequestBurndown_Q.RequestID
WHERE (((LIST_RequestBurndown_Q.MilestoneStatus)="Awaiting Approval") AND (([Request-Priority, ALL_Q].[Completed on]) Is Null))

UNION

SELECT DISTINCT [Request-Priority, ALL_Q].RequestID, "Blocked (see notes)" AS RequestStatus
FROM [Request-Priority, ALL_Q] LEFT JOIN LIST_RequestBurndown_Q ON [Request-Priority, ALL_Q].RequestID = LIST_RequestBurndown_Q.RequestID
WHERE (((LIST_RequestBurndown_Q.MilestoneStatus)="Blocked (see notes)") AND (([Request-Priority, ALL_Q].[Completed on]) Is Null))

UNION

SELECT DISTINCT [Request-Priority, ALL_Q].RequestID, "Completed - Awaiting Rollout" AS RequestStatus
FROM [Request-Priority, ALL_Q] LEFT JOIN LIST_RequestBurndown_Q ON [Request-Priority, ALL_Q].RequestID = LIST_RequestBurndown_Q.RequestID
WHERE (((LIST_RequestBurndown_Q.MilestoneStatus)="Completed") AND (([Request-Priority, ALL_Q].[Completed on]) Is Null));

查询的基本概念......基于各个里程碑的状态（LIST_RequestBurndown_Q.MilestoneStatus），确定RequestID的总体状态（[Request-Priority, ALL_Q].RequestID）。

我的问题

对于某些RequestID，会有多个状态的里程碑。例如，我可能得到如下结果：

RequestID   RequestStatus 
123         Awaiting Approval 
243         Blocked 
243         Awaiting Approval 
243         Completed - Awaiting Rollout 
542         Awaiting Approval

我想做的是＆＃34;优先考虑＆＃34;其中显示RequestStatus，因此每RequestID只有一条记录。

我一直在尝试使用ORDER BY，WHERE，DISTINCT ON来考虑如何执行此操作，或者甚至可能只创建一个包含可能状态选项的表格。相关的优先级并使用MAX - 但此时我只是过度思考这一点。任何帮助将不胜感激！

Answer 1

建议：用于对优先级进行建模的表格：

CREATE TABLE RequestStatusPrioritization
( RequestStatus VARCHAR(20) NOT NULL
     REFERENCES RequestStatuses ( RequestStatus ),
  RequestStatusRank INT NOT NULL );

...然后加入此表并返回最低（MIN）排名。

访问 - 根据字段值选择不同

我的代码

我的问题

1 个答案: