Question

我有两张桌子文件，文件类型

文件将保存所有客户端的内部和外部两种文件类型的数据我想在一行中使用内部文件路径和外部文件路径获取客户端的文件。

以下是元数据

create table filetypes (
  filetypeid int  primary key,
  typename varchar(20)
);

create table files (
  fileid int  primary key,
  filetypeid int,
  fiilepath nvarchar(200),
  client_id int
);

insert into files values (10, 1,'\testpath9\\InternalFoldername', 1);
insert into files values (11, 2,'\testpath2\\ExternalFoldername', 1);
insert into files values (12, 1,'\testpath5\\InternalFoldername', 2);
insert into files values (13, 2,'\testpath6\\ExternalFoldername', 3);


insert into filetypes values (1,'Internal');
insert into filetypes values (2,'External');

我想让SQL获取如下所示的结果

client_id   InternalPath                   ExternalPath
----------- ------------------------------ ------------------------------
1           \testpath9\\InternalFoldername \testpath2\\ExternalFoldername

Answer 1

试试这个sql语句，

 select  t1.internal_client as client_id, t1.InternalPath as InternalPath, 
 t2.ExternalPath as ExternalPath from 
 (select  client_id  as internal_client,fiilepath as InternalPath from files where filetypeid=1 ) t1 
 left join
 (select  client_id as external_client, fiilepath  as ExternalPath from files where filetypeid=2 )t2
 on t1.internal_client = t2.external_client 
 where t1.InternalPath IS NOT NULL and t2.ExternalPath IS NOT NULL

根据条件将多行列不同的值提取到单行中

1 个答案: