???????????????????￡????????????????????????????μ????????????????У?Person.Person ???LastName????nvarchar???????????????????????????????洢?????????????varchar?????


alter procedure dbo.PrecedenceTest(
@LastName varchar(50)
)
as
begin
set nocount on
select *
from Person.Person
where LastName = @LastName
end
go
exec dbo.PrecedenceTest 'Tamburello'
go


??????м?????????????????????????????

??????Index Seek???????????????????LastName????????????????????????????????????????nvarchar?????

???????????в????????????????????????????????????м????

????????????????ó????????洢?????ж??????????????????????е?????????????е???????????????????????????????????????????

???????????????????????????????

????1??user-defined data types (highest)
????2??sql_variant
????3??xml
????4??datetimeoffset
????5??datetime2
????6??datetime
????7??smalldatetime
????8??date
????9??time
????10??float
????11??real
????12??decimal
????13??money
????14??smallmoney
????15??bigint
????16??int
????17??smallint
????18??tinyint
????19??bit
????20??ntext
????21??text
????22??image
????23??timestamp
????24??uniqueidentifier
????25??nvarchar (including nvarchar(max) )
????26??nchar
????27??varchar (including varchar(max) )
????28??char
????29??varbinary (including varbinary(max) )
????30??binary (lowest)