Question

我需要能够加入另一个数据库（在同一台服务器上），并且我需要加入的数据库的名称取决于正在检查的记录。

我有一些东西

SELECT *
FROM orders o
INNER JOIN orderdetail od ON od.okey = o.okey
INNER JOIN scheduledetail scheddet on scheddet.odkey = od.odkey
INNER JOIN schedules sched on sched.schedid = scheddet.schedid
INNER JOIN databases db on db.dbdate = sched.releasedate
INNER JOIN [db.dbname].detail det on det.odkey = od.odkey

但是，据我所知，transact SQL不允许这种连接语法。有什么想法吗？

Answer 1

如果所有详细信息表都具有相同的列，则可以创建一个包装所有详细信息表的视图。

DECLARE @sql varchar(max);

SELECT
  @sql = COALESCE(@sql + ' UNION ALL ','CREATE VIEW unified_details AS ')
+ 'SELECT *,'+QUOTENAME([dbname])+' AS [dbname] FROM '+QUOTENAME([dbname])+'.[dbo].[detail]'
FROM databases;

EXEC sp_executesql @sql;

SELECT *
FROM orders o
INNER JOIN orderdetail od ON od.okey = o.okey
INNER JOIN scheduledetail scheddet on scheddet.odkey = od.odkey
INNER JOIN schedules sched on sched.schedid = scheddet.schedid
INNER JOIN databases db on db.dbdate = sched.releasedate
INNER JOIN unified_details det on det.odkey = od.odkey and db.dbname = det.dbname

T-SQL - 使用派生名称连接到数据库

1 个答案: