Question

我想写一个像

这样的查询

    select top 10 * from A
    order by price
    union
    select top 3 * from A 
    order by price

或者......那样

    select top 10 * from A
    where name like '%smt%'
    order by price
    union
    select top 3 * from A
    where name not like '%smt%'
    order by price

你能帮帮我吗？

Answer 1

这应该有效：

SELECT * 
FROM (SELECT TOP 10 A.*, 0 AS Ordinal
      FROM A
      ORDER BY [Price]) AS A1

UNION ALL

SELECT * 
FROM (SELECT TOP 3 A.*, 1 AS Ordinal
      FROM A
      ORDER BY [Name]) AS A2

ORDER BY Ordinal

来自MSDN：

在使用UNION，EXCEPT或INTERSECT运算符的查询中，ORDER BY 仅在声明结尾处被允许。此限制适用仅限于在顶级指定UNION，EXCEPT和INTERSECT时查询而不是子查询。

已修改：强制将ORDER BY应用于外部查询所需的顺序。我为两个查询添加了一个常量值列。

Answer 2

这是一种真正的hacky方式。你可能希望这些作为现实中的单独查询，但这应该给你想要的结果......

select *
from (
  select top 10 *, 1 as 'ord', price as 'ordprice' from A
  union 
  select top 3 *, 2 as 'ord', 0 as 'ordprice' from A
) a
order by ord, ordprice, name

Answer 3

UNION不喜欢UNIONed表达式中的ORDER by子句。试试这个：

SELECT * FROM
   (SELECT TOP 10 * FROM A ORDER BY Price) SetA
UNION
SELECT * FROM
   (SELECT TOP 3 * FROM a ORDER BY name) Setb
[ORDER BY something]

这会欺骗UNION运算符忽略ORDER BY，它仍然可以在TOP运算符上正常运行。如果愿意，您可以应用最终的ORDER BY来订购UNIONed集。

[现在不再适用于您的问题，因为它已被编辑！]

Answer 4

select top 10 *,0 as RS from A
union
select top 3 *,1 as RS from A 
order by
    RS,
    CASE WHEN RS=0 THEN price END, --Don't affect RS 1
    name

Answer 5

cmd.CommandText =“ SELECT 0 AS Employee_ID，'No Employees'作为Employee_FullName，'id1'Orderkey 全联盟选择Employee_ID，Employee_FullName，'id2'Orderkey 来自tblEmployee ORDER BY Orderkey，Employee_FullName”

ds = dbconn.SelectQuery（cmd）

ds.Tables（0）.Columns.Remove（ds.Tables（0）.Columns（“ Orderkey”））

通过联合使用不同的顺序

5 个答案: