实例声明中的SQL滞后

Question

如果当前CLUSTERn =上一个CLUSTERn，然后将上一个PRODCAT作为PREVCAT添加到当前行，那么我的case语句出了什么问题，我将不胜感激。

ORA-30484: missing window specification for this function
30484. 00000 -  "missing window specification for this function"
*Cause:    All window functions should be followed by window specification,
           like <function>(<argument list>) OVER (<window specification>)
*Action:
Error at Line: 11 Column: 30

SELECT  CLUSTERn,
        MEMBERn,
        COUNT(*) OVER ( PARTITION BY CLUSTERn ORDER BY MEMBERn, PRODCAT, STARTd, ENDd ) AS NEWRANK,
        CASE WHEN CLUSTERn = LAG(CLUSTERn) THEN LAG(PRODCAT) ELSE 'New' END AS PREVCAT,
        STATUS,
        PRODCAT,
        JOINTYPE,
        JOINRANK,
        CSP,
        PROGID,
        PROMNAME,
        PROMOID,
        COHORT,
        FWEEK,  
        STARTd,
        ENDd,
        SOURCE
FROM(

Answer 1

我不确定是什么令人困惑。你有：

(CASE WHEN CLUSTERn = LAG(CLUSTERn)
      THEN LAG(PRODCAT)
      ELSE 'New'
 END) AS PREVCAT,

您缺少该OVER子句-所有窗口函数的基本内容。

没有样本数据，很难确定您真正想要的是什么。也许：

(CASE WHEN CLUSTERn = LAG(CLUSTERn) OVER (ORDER BY MEMBERn, PRODCAT, STARTd, ENDd)
      THEN LAG(PRODCAT) OVER (ORDER BY MEMBERn, PRODCAT, STARTd, ENDd)
      ELSE 'New'
 END) AS PREVCAT,

也有可能CASE不需要。 LAG()具有三个参数的形式，可让您指定默认值：

LAG(PRODCAT, 1, 'NEW') OVER (PARTITION BY ClusterN ORDER BY STARTd, ENDd)