Sql 查询：将所有内容与顶部合并

Question

我想得到两个 select 语句的组合输出。

首先selectreturns某个索引的对象。第二个 select returns 最近的对象。

  declare @h geometry select @h = Geom from obj where ObjectIndex = 15054
  select ObjectIndex, Geom.STDistance(@h) from obj where ObjectIndex = 15054 
  union all
  select top( 1) ObjectIndex, Geom.STDistance(@h) from  obj WITH(index(idx_Spatial)) where Geom.STDistance(@h) < 0.0004 
  and ObjectLayerName = 'Up_Layer' order by Geom.STDistance(@h)

不幸的是，第二个语句returns对象错误。我期待最近的对象，但它 returns 第二个最近的实例。但是，当我只执行第二个 select 语句时它 returns 正确的对象。

 select top( 1) ObjectIndex, Geom.STDistance(@h) from  obj WITH(index(idx_Spatial)) where Geom.STDistance(@h) < 0.0004 
  and ObjectLayerName = 'Up_Layer' order by Geom.STDistance(@h)

感谢您的帮助。

Answer 1

Order by 将在 UNION 之后应用，尝试这样的操作

DECLARE @h GEOMETRY

SELECT @h = Geom
FROM   obj
WHERE  ObjectIndex = 15054

SELECT ObjectIndex,
       Geom.Stdistance(@h) dist
FROM   obj
WHERE  ObjectIndex = 15054
UNION ALL
SELECT ObjectIndex,
       dist
FROM  (SELECT TOP( 1) ObjectIndex,
                      Geom.Stdistance(@h) AS dist
       FROM   obj WITH(INDEX(idx_Spatial))
       WHERE  Geom.Stdistance(@h) < 0.0004
              AND ObjectLayerName = 'Up_Layer'
       ORDER  BY Geom.Stdistance(@h)) a
ORDER  BY dist

Sql 查询：将所有内容与顶部合并

Sql Query: Union All with Top

sql

union-all

sql-server-2014