Question

遵循我的存储过程

ALTER PROCEDURE [dbo].[Proc_userlogin] @userid   VARCHAR(50),
                                       @password VARCHAR(50)
AS
    DECLARE @ReturnVal VARCHAR(500)

    SET nocount ON

    IF EXISTS(SELECT username,
                     password
              FROM   clients
              WHERE  username = @userid
                     AND password = Hashbytes('SHA1', @password))
      SET @ReturnVal='0|Logged in Successfully'
    ELSE IF NOT EXISTS(SELECT username
                  FROM   clients
                  WHERE  username = @userid)
      SET @ReturnVal='1|Incorrect Username'
    ELSE IF NOT EXISTS(SELECT username,
                         password
                  FROM   clients
                  WHERE  username = @userid
                         AND password = Hashbytes('SHA1', @password))
      SET @ReturnVal='1|Incorrect Password'

    SELECT @ReturnVal

在上面的存储过程中，我正在检查用户名和密码是否输入正确。我遇到的问题是检查多个条件。可以删除多个选择查询，并使用If条件中的单选查询来检查身份验证？。可以自定义上述存储过程，以最小化if条件下的select语句数。

请建议

由于

Answer 1

我优化你的SQL代码：

ALTER PROCEDURE [dbo].[Proc_userlogin] @userid   VARCHAR(50),
                                       @password VARCHAR(50)
AS
    SET nocount ON

    DECLARE @ReturnVal VARCHAR(500)
    DECLARE @Password VARCHAR(50)
    SET @Password = NULL

    SELECT @Password = password
    FROM   clients
    WHERE  username = @userid

    IF ( @Password IS NULL )
      SET @ReturnVal='1|Incorrect Username'
    ELSE IF ( @Password = Hashbytes('SHA1', @password) )
      SET @ReturnVal='0|Logged in Successfully'
    ELSE
      SET @ReturnVal='1|Incorrect Password'

    SELECT @ReturnVal

Answer 2

感谢@Mohammad您的解决方案有效但经过一些修改

ALTER procedure [dbo].[Proc_CheckUser]
 @userid   VARCHAR(50),
 @password VARCHAR(50)
 AS
    SET nocount ON

    DECLARE @ReturnVal VARCHAR(500)
    DECLARE @PasswordOld VARCHAR(50)

    SELECT @PasswordOld = password
    FROM   Clients
    WHERE  username = @userid

    IF ( @PasswordOld IS NULL )
      SET @ReturnVal='1|Incorrect Username'
    ELSE IF ( @PasswordOld = Hashbytes('SHA1', @password) )
      SET @ReturnVal='0|Logged in Successfully'
    ELSE
      SET @ReturnVal='2|Incorrect Password'

SELECT @ReturnVal

检查SQL Server 2008上的存储过程中的多个条件

2 个答案: