简单的连接查詢解决思路

简单的连接查詢
create Table A
(
id int,
name_cn varchar(50)
)
create table B
(
idB int,
name_en varchar(50)
)
insert A
select '1','河南'
union select '2','北京'
union select '3','南京'
union select '4','深圳'

insert B
select '1','wp'
union select '1','wp'
union select '3','zhangsan'
union select '5','lisi'
union select '6','wanger'
想查詢出 :
'1','河南','wp'
'2','北京',''
'3','南京','zhangsan'
'4','深圳',''

[解决办法]

SQL code

create Table A(id int,name_cn varchar(50))create table B(idB int,name_en varchar(50))insert Aselect '1','河南'union select '2','北京'union select '3','南京'union select '4','深圳'insert Bselect '1','wp'union select '1','wp'union select '3','zhangsan'union select '5','lisi'union select '6','wanger'select * from aselect * from bselect ''''+convert(varchar(8),A.id)+''''+','+''''+a.name_cn+''''+','+''''+isnull(B.name_en,'')+''''as bname_en from A left join B on A.id =B.idB /*bname_en'1','河南','wp''2','北京','''3','南京','zhangsan''4','深圳',''*/
[解决办法]
select A.id, a.name_cn,B.name_en from A left join B on A.id =B.idB
[解决办法]
SQL code
select A.id,a.name_cn,isnull(B.name_en,'') as bname_en from A left join B on A.id =B.idB