Question

我当前的查询如下：

SELECT TOP 500
    n.NodeID as solarwinds_id,
    n.NodeName,
    n.Syslogs.MessageID,
    n.Syslogs.SysLogSeverity,
    n.Syslogs.Message,
    TOLOCAL(n.Syslogs.DateTime) as DateTime
FROM
    Orion.Nodes n
WHERE
    (n.Syslogs.DateTime > '2018-08-06 15:46:23.028792') AND n.NodeID IN (1845, 524, 38, 794, 35, 36)
ORDER BY
    n.Syslogs.DateTime DESC

但是我很快意识到，我只能从整个订购日期中获得前500个条目，也就是说，如果ID 1845有500个条目，我只会获得该ID，而没有其他。

在SQL查询中，每个ID是否有可能获得500个结果？（如果有500个）

谢谢

Answer 1

您可以使用row_number()：

SELECT n.NodeID as solarwinds_id, n.NodeName, n.Syslogs.MessageID,
       n.Syslogs.SysLogSeverity, n.Syslogs.Message, TOLOCAL(n.Syslogs.DateTime) as DateTime
FROM (SELECT n.*,
             ROW_NUMBER() OVER (PARTITION BY n.NodeId ORDER BY n.Syslogs.DateTime DESC) as seqnum
      FROM Orion.Nodes n
      WHERE n.Syslogs.DateTime > '2018 15:46:23.028792' AND
            n.NodeID IN (1845, 524, 38, 794, 35, 36)
     ) n
WHERE seqnum <= 500
ORDER BY n.Syslogs.DateTime DESC;

Answer 2

您当前的语法建议SQL Server，要使每个500获得ID个结果，您需要row_number()函数：

SELECT n.NodeID as solarwinds_id, n.NodeName, n.Syslogs.MessageID,
       n.Syslogs.SysLogSeverity, n.Syslogs.Message, TOLOCAL(n.Syslogs.DateTime) as DateTime
FROM (SELECT n.*, ROW_NUMBER() OVER (PARTITION BY NodeId ORDER BY Syslogs.DateTime DESC) as seq
      FROM Orion.Nodes n
      WHERE Syslogs.DateTime > '2018 15:46:23.028792' AND
            NodeID IN (1845, 524, 38, 794, 35, 36)
     ) n
WHERE seq <= 500
ORDER BY n.Syslogs.DateTime DESC;

Answer 3

您可以使用Rank()几乎所有数据库都具有此功能。

您可以使用CTE或临时表或子查询

以下是CTE的示例。

select * from ( SELECT 
    n.NodeID as solarwinds_id,
    n.NodeName,
    n.Syslogs.MessageID,
    n.Syslogs.SysLogSeverity,
    n.Syslogs.Message,
    TOLOCAL(n.Syslogs.DateTime) as DateTime,
    RANK() OVER (PARTITION BY n.NodeID ORDER BY  n.Syslogs.DateTime DESC) as rnk FROM
    Orion.Nodes n WHERE
    (n.Syslogs.DateTime > '2018-08-06 15:46:23.028792') AND n.NodeID IN (1845, 524, 38, 794, 35, 36))

as a  where rnk <=500

SQL查询-在多ID查询中，每个ID仅选择500个条目？

3 个答案: