Question

我有两个表，我想合并如下。

表a：

columns :a1     a2
data    :aaa    a2
         bbb    b2

表b：

columns :a1     b2
data    :aaa    a3
         ccc    c3

最终所需的输出表将包括以下内容：

决赛桌：

columns :a1     a2    b2
data    :aaa    a2    a3
         bbb    b2
         ccc          c3

Answer 1

SELECT
       a.a1, a.a2, b.b2
FROM 
       a 
FULL JOIN 
       b ON a.a1 = b.a1

Answer 2

-- Test data
with TableA(a1, a2) as
(
  select 'aaa', 'a1' union all
  select 'bbb', 'b2'
),
TableB(a1, b2) as
(
  select 'aaa', 'a3' union all
  select 'ccc', 'c3'
)


select
  coalesce(A.a1, B.A1) as a1,
  A.a2,
  B.b2
from TableA as A
  full outer join TableB as B
    on A.a1 = B.a1

结果：

a1   a2   b2
---- ---- ----
aaa  a1   a3
ccc  NULL c3
bbb  b2   NULL

Answer 3

您需要JOIN两个表格，如

SELECT a.a1, a.a2, b.b2 FROM table_a a 
JOIN table_b b ON a.a1 = b.a1

根据您的需要，您可能需要lEFT JOIN（有时称为OUTER JOIN）。实际语法还取决于您使用的数据库。这个例子适用于MySQL。

Answer 4

SELECT a.a1, a.a2, b.b2
INTO NewTable
FROM a,b
Where b.a1=a.a1

Answer 5

这应该是你要找的东西：

SELECT
       ISNULL(a.a1, b.a1) AS a1, a.a2, b.b2
FROM 
       a 
FULL OUTER JOIN 
       b ON a.a1 = b.a1

有关外部联接的更多信息，请参阅： http://msdn.microsoft.com/en-us/library/ms187518.aspx

SQL语法合并两个表？

5 个答案: