drop table a
drop table b
drop table c
go
create table a (id int)
insert into a
select 1 union
select 2 union
select 3 union
select 4 union
select 5create table b(id int,name int)
insert into b
select 1,11 union
select 2,22 union
select 13,33 union
select 14,44 union
select 15,55
create table c(name int)
insert into c
select 11 union
select 23 union
select 133 union
select 144 union
select 155select *
from (select a.id
from a join b on a.id=b.id
join c on b.name=c.name ) d
这个语句为什么在查询分析器中没返回结果呢,只是提示命令完成不是有select *
from 这语句吗?
drop table b
drop table c
go
create table a (id int)
insert into a
select 1 union
select 2 union
select 3 union
select 4 union
select 5create table b(id int,name int)
insert into b
select 1,11 union
select 2,22 union
select 13,33 union
select 14,44 union
select 15,55
create table c(name int)
insert into c
select 11 union
select 23 union
select 133 union
select 144 union
select 155select *
from (select a.id
from a join b on a.id=b.id
join c on b.name=c.name ) d
这个语句为什么在查询分析器中没返回结果呢,只是提示命令完成不是有select *
from 这语句吗?
select *
from (select a.id
from a a join b b on a.id=b.id
join c c on b.name=c.name ) d
当 SET NOCOUNT 为 OFF 时,返回计数。 会显示:
(5 行受影响)(5 行受影响)(5 行受影响)(1 行受影响)
如果存储过程中包含的一些语句并不返回许多实际的数据,则该设置由于大量减少了网络流量,因此可显著提高性能。