NULL轉換爲空字符串的SQL Server

Question

我得到了「AltReimMethod」空值，這是我要轉換爲空字符串 這裏的查詢：

(SELECT rc.name from ReimbursementChoice rc WHERE rc.admin_id = a.admin_id AND rc.choice_id = pe.alt_payment_choice) AS 'AltReimMethod' 

我試圖

(SELECT (ISNULL(rc.name,' ')) from ReimbursementChoice rc WHERE rc.admin_id = a.admin_id AND rc.choice_id = pe.alt_payment_choice) AS 'AltReimMethod' 

也

(SELECT (ISNULL(CONVERT(varchar(50),rc.name),' ')) from ReimbursementChoice rc WHERE rc.admin_id = a.admin_id AND rc.choice_id = pe.alt_payment_choice) AS 'AltReimMethod' 

他們不顯示任何錯誤，但I D甚至ONT得到任何結果 幫助儘快

Answer 1

上查詢應用ISNULL內部沒有查詢申請isnhull

ISNULL((SELECT rc.name from ReimbursementChoice rc WHERE 
rc.admin_id = a.admin_id AND rc.choice_id = pe.alt_payment_choice),' ') 
AS 'AltReimMethod'