Sql 为每个查询选择最新更新

我有两个表，需要创建一个查询，用最新的日志更新返回所有当前打开的查询

表-sv_查询

inquiry_id | status  | state       | owner_grp |
------------------------------------------------
1            OPEN     Acknowledged    DEV
2            OPEN     Acknowledged    DEV
3            OPEN     Reassigned      DEV
4            OPEN     Reassigned      DEV

表-sv_日志

diary_id| inquiry_id | change_dt| change_uid |
------------------------------------------------
1          1           2/1/2013    JBLOGGS
2          1           3/1/2013    JBLOGGS
3          1           4/1/2013    JSMITH
1          2           2/1/2013    JBLOGGS
2          2           4/1/2013    JSMITH
1          3           4/1/2013    JSMITH
2          3           6/1/2013    JBLOGGS
1          4           5/1/2013    JBLOGGS
2          4           8/1/2013    JBLOGGS

我现在使用的代码是

SELECT 
  t1.inquiry_id, 
  t1.state, 
  t1.status, 
  t1.business_impact, 
  t1.priority, 
  t1.owner_rep, 
  t1.owner_grp, 
  t2.change_dt as diary_updated, 
  t2.change_uid as diary_updated_by  
FROM sv_inquiry t1
JOIN sv_diary t2 
  on t1.inquiry_id = t2.inquiry_id
WHERE 
  owner_grp = 'DEV' 
  AND state <> 'Closed' 
  AND status is not null

但是，当我只需要基于sv_日记表中的日期的最新日记条目时，这会返回每个查询的所有日记条目。我该怎么做

为表格的垃圾格式道歉，但我不能想出如何在这个网站上创建一个像样的表格结构

谢谢

请尝试通过以下方式分组：

SELECT tt.*,
        t2.change_dt,
        t2.change_uid   
FROM
(
    SELECT  t1.inquiry_id, 
            t1.state, 
            t1.status, 
            t1.business_impact, 
            t1.priority, 
            t1.owner_rep, 
            t1.owner_grp, 
            MAX(t2.diary_id) as diary_id
    FROM sv_inquiry t1
    JOIN sv_diary t2 on t1.inquiry_id = t2.inquiry_id
    WHERE owner_grp = 'DEV' 
    AND state <> 'Closed' 
    AND status is not null
    GROUP BY t1.inquiry_id, t1.state, t1.status, t1.business_impact, t1.priority, t1.owner_rep, t1.owner_grp, 
) tt
INNER JOIN sv_diary td on t1.inquiry_id = t2.inquiry_id

---

您可以尝试以下查询：-

SELECT t1.inquiry_id, t1.state, t1.status, t1.business_impact, t1.priority, t1.owner_rep, t1.owner_grp, 
 t2.change_dt as diary_updated, t2.change_uid as diary_updated_by  
FROM sv_inquiry t1
JOIN (select * from (select d.*,row_number(over partition by inquiry_id order by dairy_updated desc) rn from sv_diary d) where rn =1) t2 on t1.inquiry_id = t2.inquiry_id
WHERE owner_grp = 'DEV' 
AND state <> 'Closed' 
AND status is not null

我还没有测试过，所以如果你发现任何问题，请告诉我。

---

我在这里使用了分析查询，它比子查询工作得更快。您必须按日期列排序，并将其限制为第一个元素：

MYSQL： SQL Server 如果您使用的是不同的dbms，则可以执行类似的操作来完成此操作。

尝试以下操作：

SELECT t1.inquiry_id, t1.state, t1.status, t1.business_impact, t1.priority,
    t1.owner_rep, t1.owner_grp, t2.change_dt as diary_updated,
    t2.change_uid as diary_updated_by
FROM sv_inquiry t1
    LEFT JOIN (
        SELECT t1.*
        FROM sv_diary t1 JOIN(
            SELECT inquery_id, MAX(change_dt)
            FROM sv_diary
            GROUP BY inquery_id
        ) t2 ON t1.inquery_id = t2.inquery_id AND t1.change_dt = t2.change_dt 
    ) t2 on t1.inquiry_id = t2.inquiry_id
WHERE t1.owner_grp = 'DEV' 
    AND t1.state <> 'Closed' 
    AND t1.status is not null

---

你说的最新日记更新是什么意思？今天完成的所有更新？您使用的是什么数据库mysql/Microsoft SQL Server？请使用having语句获取最近的日期！

SELECT 
  t1.inquiry_id, 
  t1.state, 
  t1.status, 
  t1.business_impact, 
  t1.priority, 
  t1.owner_rep, 
  t1.owner_grp, 
  t2.change_dt as diary_updated, 
  t2.change_uid as diary_updated_by  
FROM sv_inquiry t1
JOIN sv_diary t2 
  on t1.inquiry_id = t2.inquiry_id
WHERE 
  owner_grp = 'DEV' 
  AND state <> 'Closed' 
  AND status is not null
ORDER BY t2.change_dt DESC
LIMIT 1;

SELECT TOP 1
  t1.inquiry_id, 
  t1.state, 
  t1.status, 
  t1.business_impact, 
  t1.priority, 
  t1.owner_rep, 
  t1.owner_grp, 
  t2.change_dt as diary_updated, 
  t2.change_uid as diary_updated_by  
FROM sv_inquiry t1
JOIN sv_diary t2 
  on t1.inquiry_id = t2.inquiry_id
WHERE 
  owner_grp = 'DEV' 
  AND state <> 'Closed' 
  AND status is not null
ORDER BY t2.change_dt DESC;

SELECT t1.inquiry_id, t1.state, t1.status, t1.business_impact, t1.priority,
    t1.owner_rep, t1.owner_grp, t2.change_dt as diary_updated,
    t2.change_uid as diary_updated_by
FROM sv_inquiry t1
    LEFT JOIN (
        SELECT t1.*
        FROM sv_diary t1 JOIN(
            SELECT inquery_id, MAX(change_dt)
            FROM sv_diary
            GROUP BY inquery_id
        ) t2 ON t1.inquery_id = t2.inquery_id AND t1.change_dt = t2.change_dt 
    ) t2 on t1.inquiry_id = t2.inquiry_id
WHERE t1.owner_grp = 'DEV' 
    AND t1.state <> 'Closed' 
    AND t1.status is not null