从两个表SQL Server中选择和插入的一种更优雅的方式

I have 2 tables like:

我有两张桌子:

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


ID NAME
-------------
1  var
2  var2
3  var3
4  var4
...

I want to insert in a @table 2 results from table1, and, 3 results from table2, with different ID, Currently I have something like:

我想在表1中插入一个@table 2的结果，从table2中得到3个结果，有不同的ID，现在我有一些类似的东西:

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

I get the expected values, but...

我得到了期望值，但是…

Is there a more elegant way to do this? I guess I´m doing more than needed.
有更优雅的方法吗?我想我´m比需要做更多。

P.D. I get something like:

我得到的是:

field1  field2 field3 field4 field5
-------------------------------------
val1     var2    val4   val7   var7

2 个解决方案

#1

If ID is a primary key or unique key in Table1 and Table 2 you can do this instead.

如果ID是表1和表2中的主键或惟一键，则可以这样做。

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)

#2

I'm not sure if it's more elegant, but here's a different query that does the same.

我不确定它是否更优雅，但这里有一个不同的查询也做同样的事情。

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)) ;

It uses a common table expression (CTE) to create a union of the two tables. It also pivots the data using the MAX aggregation. You can also do this with the PIVOT operator.

它使用公共表表达式(CTE)创建两个表的联合。它还使用最大聚合来透视数据。你也可以用主算子来做。

#1