NULL转换为空字符串的SQL Server

Question

我得到了“AltReimMethod”空值，这是我要转换为空字符串 这里的查询：

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

我试图

(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' 

他们不显示任何错误，但I D甚至ONT得到任何结果 帮助尽快

Answer 1

上查询应用ISNULL内部没有查询申请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'