多個子查詢

Question

我可以在一個查詢中使用多個WITH子查詢嗎？

;WITH x AS (
    SELECT ... 
), 
WITH y AS (
    SELECT ... 
) 
SELECT * FROM z 
INNER JOIN x ON ... 
INNER JOIN y ON ... 

Answer 1

這就是所謂的common table expression，是的，你可以使用多個CTE的，只用一個WITH並刪除第二with這樣的：

WITH x AS (
    SELECT ... 
),y AS (
    SELECT ... 
) 
SELECT * FROM z 
INNER JOIN x ON ... 
INNER JOIN y ON ...