从SQL Server中选择和插入两个表的更优雅的方法

从SQL Server中选择和插入两个表的更优雅的方法,sql,tsql,sql-server-2008,Sql,Tsql,Sql Server 2008,我有两张桌子,像: ID NAME ------------- 1 someValue 2 someValue 3 someValue 4 someValue ... ID NAME ------------- 1 var 2 var2 3 var3 4 var4 ... 我想在@表中插入表1中的2个结果,以及表2中的3个结果,使用不同的ID,目前我有如下内容: Declare @vars TABLE( field1 varchar(80),

我有两张桌子,像:

ID NAME
-------------
1  someValue
2  someValue
3  someValue
4  someValue
...


ID NAME
-------------
1  var
2  var2
3  var3
4  var4
...
我想在
@表中插入表1中的2个结果,以及表2中的3个结果,使用不同的ID,目前我有如下内容:

Declare @vars TABLE(
        field1  varchar(80),
        field2  varchar(80),
        field3  varchar(80),
        field4  varchar(80),
        field5  varchar(80)
    )

INSERT INTO @vars(field1, field2, field3, field4, field5)
    SELECT  a.Name,
            b.Name,
            c.Name,
            d.Name,
            e.Name
    FROM    @Table1  a,
            @Table1  b, 
            @Table2  c,
            @Table2  d,
            @Table2  e
    WHERE   a.ID = 1 
    AND     b.ID = 25
    AND     c.ID = 12 
    AND     d.ID = 25 
    AND     e.ID = 14 
field1  field2 field3 field4 field5
-------------------------------------
val1     var2    val4   val7   var7
我得到了期望值,但是

  • 还有更优雅的方式吗 这我想我做的不止这些 需要
医生。 我得到的结果是:

Declare @vars TABLE(
        field1  varchar(80),
        field2  varchar(80),
        field3  varchar(80),
        field4  varchar(80),
        field5  varchar(80)
    )

INSERT INTO @vars(field1, field2, field3, field4, field5)
    SELECT  a.Name,
            b.Name,
            c.Name,
            d.Name,
            e.Name
    FROM    @Table1  a,
            @Table1  b, 
            @Table2  c,
            @Table2  d,
            @Table2  e
    WHERE   a.ID = 1 
    AND     b.ID = 25
    AND     c.ID = 12 
    AND     d.ID = 25 
    AND     e.ID = 14 
field1  field2 field3 field4 field5
-------------------------------------
val1     var2    val4   val7   var7

我不确定它是否更优雅,但这里有一个不同的查询,它也有同样的功能

WITH myTables AS
    ( SELECT ID, NAME, 'Table1' AS SOURCE
    FROM Table1

    UNION ALL

    SELECT ID, NAME, 'Table2' AS SOURCE
    FROM Table2
    )
INSERT INTO @vars(field1, field2, field3, field4, field5)
SELECT MAX(CASE WHEN source = 'Table1' AND id = 1  THEN NAME END) AS field1,
    MAX(CASE    WHEN source = 'Table1' AND id = 25 THEN NAME END) AS field2,
    MAX(CASE    WHEN source = 'Table2' AND id = 12 THEN NAME END) AS field3,
    MAX(CASE    WHEN source = 'Table2' AND id = 25 THEN NAME END) AS field4,
    MAX(CASE    WHEN source = 'Table2' AND id = 14 THEN NAME END) AS field5
FROM myTables
WHERE SOURCE = ('Table1'  AND ID IN (1, 25))
    OR (SOURCE = 'Table2' AND ID IN (12, 25, 14)) ;

它使用公共表表达式(CTE)创建两个表的并集。它还使用MAX聚合来透视数据。您也可以使用PIVOT操作符执行此操作。

如果ID是表1和表2中的主键或唯一键,则可以执行此操作

insert into @vars
select
  (select Name from @Table1 where ID = 1),
  (select Name from @Table1 where ID = 25),
  (select Name from @Table2 where ID = 12),
  (select Name from @Table2 where ID = 25),
  (select Name from @Table2 where ID = 14)

使用
table1,table2,table3,…
old-style-JOIN语法,如果你不注意的话,你肯定会有笛卡尔积!我建议始终使用新的标准化ANSI连接语法:
内部连接、左侧外部连接、右侧外部连接
等等嘿,这不公平!我打算发布一个比OP更优雅的解决方案。你应该在之后发布,以超越所有人!:)+1.