How to decode password from sys.syslogins table

问题:

I have a program in which the user needs to login with user name and password. I'm checking the name from the sys.syslogins table in master db. But for the password I receive a string with (probably) coded characters like this (1?????????????). Now what can I do in order to decode that string and take the password in order to compare with the enter it one?

回答1:

Try this:

SELECT name FROM sys.syslogins
WHERE pwdcompare('somepassword', password) = 1

Edited to replace double quotes with single quotes.

回答2:

You can't decode sys.syslogins: it's a one way hash.

You compare like for like if it uses the same technique or run it through pwdcompare

Note: it's also sys.sql_logins in SQL Server 2005+

Also, why would you use SQL Server logins to validate a user? It doesn't make sense...