连接的T-SQL问题
我正试图通过两个数据集实现我文章末尾的连接的T-SQL问题,sql,sql-server,tsql,join,Sql,Sql Server,Tsql,Join,我正试图通过两个数据集实现我文章末尾的预期结果。我正在使用左连接,这无助于我获得预期的结果。我想从两个表中获取所有匹配和不匹配的记录 用于创建和检索数据集和我的当前结果集的查询如下: select a.id, a.name, a.rev, isnull(b.conv, 0) as conv from (select 1 as id, 'A' as name, 2 as rev, 0 as conv union all select
预期结果。我正在使用左连接
,这无助于我获得预期的结果。我想从两个表中获取所有匹配和不匹配的记录
用于创建和检索数据集和我的当前结果集的查询如下:
select
a.id, a.name, a.rev, isnull(b.conv, 0) as conv
from
(select
1 as id, 'A' as name, 2 as rev, 0 as conv
union all
select
2 as id, 'B' as name, 1 as rev, 0 as conv) a
left join
(select
1 as id, 'A' as name, 0 AS rev, 2 as conv
union all
select
3 as id, 'C' as name, 0 as rev, 3 as conv) b on a.id = b.id
使用左联接的上述查询的当前结果:
id name rev conv
---------------------
1 A 2 2
2 B 1 0
预期结果:
id name rev conv
--------------------
1 A 2 2
2 B 1 0
3 C 0 3
改用完全联接
:
SELECT ISNULL(a.id,b.id) id,
ISNULL(a.name,b.name) name,
ISNULL(a.rev,0) rev,
ISNULL(b.conv,0) conv
FROM ( SELECT 1 as id , 'A' as name , 2 as rev, 0 as conv
UNION ALL
SELECT 2 as id , 'B' as name, 1 as rev, 0 as conv) a
FULL JOIN ( SELECT 1 as id , 'A' as name, 0 AS rev, 2 as conv
UNION ALL
SELECT 3 as id , 'C' as name, 0 as rev, 3 as conv) b
ON a.id = b.id
ORDER BY ISNULL(a.id,b.id);
您应该尝试使用完全外部联接,这将结合左联接和右联接的结果
辛塔克斯:
SELECT column_name(s)
FROM
table1 FULL OUTER JOIN table2
ON
table1.column_name = table2.column_name;
我希望有帮助 请查看以更好地了解联接。