从sql server中的两个表中获取记录

Question

我在sql server中有两个这样的表。

表1

userid    value
a          1  
b          1
c          1
d          1

表2

userid         value
e                0
f                0
g                0
a                0
b                0

我想从上面的两个表

输出这样的内容

usrid           value
a                0
b                0 
c                1
d                1
e                0
f                0 
g                0

如果表1中存在任何记录，则记录必须从表2中获取数据，如果表1中不存在用户ID，则仅从表2中获取数据。

Answer 1

试试这个：

SELECT *
FROM   table1
WHERE  table1.userid NOT IN (select userid from table2)

UNION

SELECT *
FROM   table2

Answer 2

试试这个：

select  ISNULL(t1.usrid,t2.usrid) as usrid
       ,ISNULL(t1.value,t2.value) as value
from table1 t1
outer join table2 t2 on t1.usrid = t2.usrid

Answer 3

试试这个

SELECT * FROM dbo.Table_2 AS t WHERE t.uid  IN (SELECT t2.uid FROM dbo.Table_1 AS t2)
UNION
SELECT * FROM dbo.Table_1 AS t WHERE t.uid NOT IN (SELECT t2.uid FROM dbo.Table_2 AS t2)
UNION
SELECT * FROM dbo.Table_2 AS t WHERE t.uid NOT IN (SELECT t2.uid FROM dbo.Table_1 AS t2)

Answer 4

试试这个

SELECT *
FROM   table1
WHERE  userid NOT IN (select userid from table2)
UNION
SELECT *
FROM   table2