Web page search and SQL

Here is a way to search many columns in a table:

CREATE PROCEDURE [dbo].[SearchExample] (
@userId UNIQUEIDENTIFIER = NULL,   --set all parameters' default value to null
@firstName NVARCHAR(50) = NULL,
@lastName NVARCHAR(50) = NULL,
@address NVARCHAR(100) = NULL,
@zipcode INT = NULL
)

SELECT ...  --omit
FROM   dbo.UserInfo u
WHERE  u.userId = COALESCE(@userId, u.userId)
AND    u.firstName LIKE ('%'+ COALESCE(@firstName, u.firstName)+'%')
AND    ...  --omit
...    --omit

Set the default value to null for all the input parameters is because if we don't have any filter to search (the value is null), then COALESCE() will use the second parameter as the output, otherwise it will output the first parameter.
For example, if @userId = 1001, the

WHERE  u.userId = COALESCE(@userId, u.userId)

will become like

WHERE  u.userId = 1001

Otherwise, it will become like

WHERE  u.userId = u.userId