MS SQL 插入数据问题？

当表为空时可以向其中插入9999条随即产生的数据，但当表不为空时，插入9999数据时只能插入1598条数据（每次都是1598），但是当再次执行插入数据时（无论插入多少），上次少插入的8401条数据会再表中显示出来，这是为什么？
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ALTER proc [dbo].[usp_addCard]
@cardName varchar(50),
@cardpValue int,
@cardPrice float,
@num int
as
begin
declare @cardId varchar(50),@cardpwd varchar(50),@i int
set @i = 0
if exists(select name from (select name = @cardName)a where name like '%魔兽%')
begin
while @i < @num
begin
select @cardId = 'MS'+convert(varchar(50),convert(varchar(50),cast(RAND()*100000 as int))+convert(varchar(50),cast(RAND()*1000000 as int))+convert(varchar(50),cast(RAND()*1000000 as int)))
select @cardpwd = convert(varchar(50),convert(varchar(50),cast(RAND()*100000 as int))+convert(varchar(50),cast(RAND()*1000000 as int)))
insert into tb_card values(@cardId,@cardName,@cardpwd,@cardPrice,@cardpValue,'images/card/2.jpg')
set @i = @i+1
end
end
else if exists(select name from (select name = @cardName)a where name like '%网易%')
begin
while @i < @num
begin
select @cardId = 'WY'+convert(varchar(50),convert(varchar(50),cast(RAND()*100000 as int))+convert(varchar(50),cast(RAND()*1000000 as int))+convert(varchar(50),cast(RAND()*1000000 as int)))
select @cardpwd = convert(varchar(50),convert(varchar(50),cast(RAND()*100000 as int))+convert(varchar(50),cast(RAND()*1000000 as int)))
insert into tb_card values(@cardId,@cardName,@cardpwd,@cardPrice,@cardpValue,'images/card/1.jpg')
set @i = @i+1
end
end
end

这是我的SQL语句，
执行 insert ..9999条.. 结果为 9999行影响，
删除完；
执行 insert ..1条.. 结果为 1行影响，
执行 insert ..9999条.. 结果为 1599行，
执行 insert ..1条.. 结果为 10001
谁能帮忙解释下？？？？？