left join on 后and 和 where 的区别实例讲解

create table A(
    ID int identity(1,1) not null,
    AName nvarchar(300) null
)
create table B(
    ID int identity(1,1) not null,
    BID int  not null,
    BName nvarchar(300) null
)


insert into B(BName,BID) values(N'小明',2)
insert into B(BName,BID) values(N'小网',1)
insert into B(BName,BID) values(N'小刚',1)
insert into B(BName,BID) values(N'小蒋',1)
insert into B(BName,BID) values(N'小赵',1)
insert into B(BName,BID) values(N'小流',1)


insert into A(AName) values(N'一班')
insert into A(AName) values(N'二班')
insert into A(AName) values(N'三班')