符和子查询之间,作用类似Exists、not exists、in、not in以及其他逻辑意义,这些语法同样被SQLServer2000支持但是很少看到有人用它们。
set nocount on
use tempdb
go
if (object_id ('t1' ) is not null ) drop table t1
create table t1 (n int )
insert into t1 select 2 union select 3
if (object_id ('t2' ) is not null ) drop table t2
create table t2 (n int )
insert into t2 select 1 union select 2 union select 3 union select 4
select *
From t2 where n> all (select n f
rom t1 ) --4
select * from t2 where n> any (select n from t1 ) --3,4
-
-select * from t2 where n>some(select n from t1) --3,4
select * from t2 where n= all (select n from t1 ) --无数据
select * from t2 where n= any (select n from t1 ) --2,3
--select * from t2 where n=some(select n from t1) --2,3
select * from t2 where n< all (select n from t1 ) --1
select * from t2 where n< any (select n from t1 ) --1,2
--select * from t2 where n<some(select n from t1) --1,2
select * from t2 where n<> all (select n from t1 ) --1,4
select * from t2 where n<> any (select n from t1 ) --1,2,3,4
--select * from t2 where n<>some(select n from t1)--1,2,3,4
set nocount off
他们逻辑上意义很像但是对于null的处理却是恰恰相反,第一句会忽略子查询的null而把t2的null同时查出来,第二句却是忽略了t2的null同时会因为t1中的null而无法查询到数据。