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当我执行以下代码时，我得到的结果如下：

ID  column1 column2 

34  NULL    NULL
34  Org13   Org13
36  NULL    NULL
36  NULL    Org2
36  Org4    NULL
41  NULL    NULL
41  NULL    Org5
41  Org3    NULL

我希望我的结果看起来像：

ID  column1  column2

34  Org13   Org13
36  Org4    Org2
41  Org3    Org5

我有两张桌子：Table1 和 Table2。Table2 是一个查找表，包含以下字段：id、name

表 1 具有以下字段（id、column1、column2）。column1 和 column2 都与查找表有外键关系：

FK_1: Table1.column1-Table2.id
FK_2: Table1.column2-Table2.id

由于我想提取 column1 和 column2 的值，并且由于这两个值都是在同一字段（Table2.name）上的查找，我怀疑我需要进行内部选择。

我的代码如下。我该如何更改它以产生所需的结果，而不是我得到的结果？提前致谢！

DECLARE @value INT
SET @value = 14

SELECT DISTINCT 
    Table1.[id]         AS ID
    , ( SELECT DISTINCT
            Table2.[name] 
        WHERE 
            Table1.column1 =
            Table2.id ) AS column1
    , ( SELECT DISTINCT
            Table2.[name] 
        WHERE 
            Table1.column2 =
            Table2.id ) AS column2
FROM 
    Table1
    ,Table2
WHERE   
    Table1.[id] = @value
4

3 回答 3

3 
    /*
    create table table1(id int, col1 int, col2 int);
    create table table2(id int, name varchar(10) );

    insert into table2 values(1, 'org 1');
    insert into table2 values(2, 'org 2');
    insert into table2 values(3, 'org 3');
    insert into table2 values(4, 'org 4');

    insert into table1 values(1, 1, 2);
    insert into table1 values(2, 2, 2);
    insert into table1 values(3, 2, 3);
    insert into table1 values(4, 4, 1);
    */

    select
        a.id,
        b.name as column1,
        c.name as column2
    from
         table1 a
    join table2 b on b.id = a.col1
    join table2 c on c.id = a.col2;


 id     column1     column2    
 -----  ----------  ---------- 
 1      org 1       org 2      
 2      org 2       org 2      
 3      org 2       org 3      
 4      org 4       org 1      

 4 record(s) selected [Fetch MetaData: 3/ms] [Fetch Data: 0/ms] 

 [Executed: 7/7/09 4:07:25 PM EDT ] [Execution: 1/ms]
于 2009-07-07T20:08:05.667 回答
2 
DECLARE @value INT
SET @value = 14

SELECT
    t1.[id]                 AS ID
    MAX(t2a.name),
    MAX(t2b.name)
FROM 
    Table1 t1
    LEFT JOIN
    Table2 t2a ON t1.column1 = t2a.id
    LEFT JOIN
    Table2 t2b ON t1.column2 = t2b.id
WHERE   
    t1.[id] = @value
GROUP BY    
    t1.[id]
于 2009-07-07T19:51:19.943 回答
2

gbn，我想你的意思是写

DECLARE @value INT
SET @value = 1

SELECT --??? DISTINCT 
    t1.[id] AS ID, --- missed comma
    table2a.name,
    table2b.name
FROM 
   Table1 t1
     JOIN Table2 table2a ON t1.column1 = table2a.id
     JOIN Table2 table2b ON t1.column2 = table2b.id -- you have t1.column1 oops
WHERE   
    t1.[id] = @value
于 2009-07-07T20:09:39.547 回答