sql With(NoLock),With(ReadPast)

---------------
create table tmp1
( 
    id int primary key,
    name nvarchar(20)
)

-----------
insert into tmp1(id,name) values(1,'zhsan1');
insert into tmp1(id,name) values(2,'lisi1');

-------------------------------
select * from tmp1

更新（Update）語句對資料庫加鎖

-----------------------------
begin tran tran1
    update tmp1 set name='zhsan' where id=1
-------------------------------
select * from tmp1

查詢一直在進行，此時表已經被鎖住了

-------------------------------
update tmp1 set name='lisi' where id=2
-------------------------------
select * from tmp1 where id>1

-------------------------------
delete from tmp1 where id=2
-------------------------------
select * from tmp1 where id>1

查詢，更新，刪除除被鎖定的那行數據都能成功，說明被鎖住的只有id=1的那一行，對其他行的查詢，更新及刪除無影響

插入語句

-------------------------------
insert into tmp1(id,name) values(3,'lisi')
-------------------------------
select * from tmp1 where id>1

結果執行成功，說明插入不受影響

 先將資料庫還原為

-----------------------------
begin tran tran1
    update tmp1 set name='zhsan' where id=1

with(readpast)與with(nolock)

-------------------------------
select * from tmp1 with(readpast)

-------------------------------
select * from tmp1 with(nolock)

with(readpast)會忽略被鎖住的那一行，with(nolock)不會