如何将 proc sql table 中的行数限制为包含最高日期的行数

How do I limit the number of rows in a proc sql table to ones which contain the highest date

我正在尝试在我的大型机上执行大型查询,我需要做的是下拉所有具有最高 PD_START_DATE 的行。我认为它类似于

PROC SQL ;
SELECT PD_PROP_NUM, PD_RATE_PGM, PD_START_DATE, PD_END_DATE, PD_DOW_FREQ, PD_ROOM_POOL, PD_QUOTE_SERIES, PD_RPGM_SEQ_NUM, PD_PROD_LINE 
FROM Sbtddraf.nycomnidat
(SELECTorder by PD_START_DATE 
DESC 
NOBS =PD_START_DATE(MAX) 

但我知道这行不通; 建议表示赞赏

如果您使用直通 SQL 您的数据库支持 window 函数(它可能支持),那么您可以:

PROC SQL ;
    SELECT PD_PROP_NUM, PD_RATE_PGM, PD_START_DATE, PD_END_DATE, PD_DOW_FREQ, PD_ROOM_POOL, PD_QUOTE_SERIES, PD_RPGM_SEQ_NUM, PD_PROD_LINE 
    FROM (SELECT n.*,
                 ROW_NUMBER() OVER (PARTITION BY PD_PROP_NUM ORDER BY PD_START_DATE DESC) as seqnum
          FROM Sbtddraf.nycomnidat n
         ) n
    WHERE seqnum = 1;

如果这行不通,还有其他方法可以表达这个逻辑。

编辑:

这是一个替代方案:

PROC SQL ;
    SELECT PD_PROP_NUM, PD_RATE_PGM, PD_START_DATE, PD_END_DATE, PD_DOW_FREQ, PD_ROOM_POOL, PD_QUOTE_SERIES, PD_RPGM_SEQ_NUM, PD_PROD_LINE 
    FROM Sbtddraf.nycomnidat n
    WHERE n.PD_START_DATE = (SELECT MAX(n2.PD_START_DATE)
                             FROM Sbtddraf.nycomnidat n2
                             WHERE n2.PD_PROP_NUM = n.PD_PROP_NUM
                            );

注意 WHERE 子句。这就是说您想要每个 PD_PROP_NUM.

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