的Sybase替代的DENSE_RANK（）OVER（PARTITION BY

Question

我有以下SQL查詢，需要將其轉換到Sybase

SELECT prd_name, DENSE_RANK() OVER (PARTITION BY prd_cat ORDER BY createddt) FROM product 

表腳本：

CREATE table product(prd_name varchar(10), 
        prd_cat varchar(10), 
        createddt datetime) 
INSERT INTO product values('Product 1', 'Toy', CONVERT(DATE,'2017-05-30')) 
INSERT INTO product values('Product 2', 'Toy', CONVERT(DATE,'2017-05-31')) 
INSERT INTO product values('Product 3', 'Toy', CONVERT(DATE,'2017-05-31')) 
INSERT INTO product values('Product 4', 'Toy1', CONVERT(DATE,'2017-05-29')) 

版本：Adaptive Server Enterprise的/ 15.7

Answer 1

某些版本的Sybase支持窗口函數我假設你沒有這樣的版本

您可以將其替換爲相關的子查詢：

SELECT p.prd_name, 
     (SELECT COUNT(DISTINCT createddt) 
     FROM product p2 
     WHERE p2.prd_cat = p.prd_cat AND p2.createddt < p.createddt 
     ) 
FROM product p;