Question

我有一个过程，需要绕过输入为null的WHERE子句。

请找到以下条件。

CREATE PROCEDURE [dbo].[spPERSON_SELECT]    
(
@PersonID INT = NULL,
@OrganizationID INT = NULL,
@ManagerID INT = NULL 
)
AS

BEGIN
SELECT PERSON.name, ORGANIZATION.name,PERSON.manager 
FROM PERSON 
    INNER JOIN ORGANIZATION 
        ON PERSON.person_id = ORGANIZATION.person_id    
WHERE PERSON.person_id = @PersonID  
    and ORGANIZATION.organization_id = @OrganizationID  
    and PERSON.manager_id = @ManagerID 

END
GO

Iam面临一个问题，而输入为null，在这种情况下需要避免where条件。

示例：

如果@PersonID为null，那么我的select查询需要以下结构：

SELECT PERSON.name, ORGANIZATION.name,PERSON.manager 
FROM PERSON 
    INNER JOIN ORGANIZATION 
        ON PERSON.person_id = ORGANIZATION.person_id    
WHERE ORGANIZATION.organization_id = @OrganizationID
    and PERSON.manager_id = @ManagerID

我想避免动态查询。

Answer 1

括起每个参数并测试无效，即

(PERSON.manager_id=@ManagerID or @ManagerID is NUll)

Answer 2

SELECT PERSON.name, ORGANIZATION.name, PERSON.manager 
FROM PERSON 
INNER JOIN ORGANIZATION ON PERSON.person_id=ORGANIZATION.person_id
WHERE 
(@PersonID is null or PERSON.person_id=@PersonID) 
and (@OrganizationID is null or ORGANIZATION.organization_id=@OrganizationID)
and (@ManagerID is null or PERSON.manager_id=@ManagerID)

Answer 3

我个人最喜欢的方法是：

WHERE PERSON.manager_id = COALESCE(@ManagerID, PERSON.manager_id)

对每个参数使用coalesce看起来更好。

即使@ManagerID IS NULL始终匹配自己PERSON.manager_id，也会匹配，但如果@ManagerID IS NOT NULL则停止。

值得注意的是，您可以根据需要提供COALESCE(expression1, expression2, n)个参数。

当filter参数为null时绕过WHERE子句

3 个答案: