sql server - example - Seleccione stmt con ROW_NUMBER() OVER(PARTITION BY...) en Where clause

sql row number over

Question

Debo estar haciendo algo mal. Estoy intentando usar la función row_number para seleccionar solo los valores que tienen un Rownum de 1 , para que siempre obtenga el último índice . Sin embargo rownum no se reconoce en la cláusula where.

SELECT  fs.docu_id as docID 
, fs.field_3 AS ProductNo
, fs.field_4 AS [Status]
, fs.field_5 AS [Index]
,pd.[doku_nr] AS docIDshort
, ROW_NUMBER() OVER(PARTITION BY fs.field_3 ORDER BY fs.field_5 Desc) AS rownum
FROM [table1] fs
JOIN [table2] pd
ON fs.docu_id=pd.docu_id 
AND  fs.field_4 = ''valid''

¿Qué me estoy perdiendo? ¿Debo crear una stmt de selección diferente?

Gracias.

Answer 1

No puede usar funciones de ventana en la cláusula Where (solo en SELECT u ORDER BY ).

Pero podría usar un CTE en su lugar:

WITH CTE
     AS (SELECT fs.docu_id                    AS docID, 
                fs.field_3                    AS ProductNo, 
                fs.field_4                    AS [Status], 
                fs.field_5                    AS [Index], 
                pd.[doku_nr]                  AS docIDshort, 
                Row_number() OVER( 
                    Partition BY fs.field_3 
                    ORDER BY fs.field_5 DESC) AS rownum 
         FROM   [table1] fs 
                JOIN [table2] pd 
                  ON fs.docu_id = pd.docu_id 
                     AND fs.field_4 = ''valid'') 
SELECT docid, productno, status, [index], docIDshort 
FROM   CTE
WHERE  rownum = 1