在SQL Server中，可以使用insert将行插入到表中。。SELECT语句：
INSERT INTO Table (col1, col2, col3)
SELECT col1, col2, col3
FROM other_table
WHERE sql = 'cool'
是否也可以使用SELECT更新表？我有一个包含这些值的临时表，并希望使用这些值更新另一个表。也许是这样的：
UPDATE Table SET col1, col2
SELECT col1, col2
FROM other_table
WHERE sql = 'cool'
WHERE Table.id = other_table.id
当前回答
如果你想加入表本身（这不会经常发生）：
update t1 -- just reference table alias here
set t1.somevalue = t2.somevalue
from table1 t1 -- these rows will be the targets
inner join table1 t2 -- these rows will be used as source
on .................. -- the join clause is whatever suits you
其他回答
UPDATE
Table_A
SET
Table_A.col1 = Table_B.col1,
Table_A.col2 = Table_B.col2
FROM
Some_Table AS Table_A
INNER JOIN Other_Table AS Table_B
ON Table_A.id = Table_B.id
WHERE
Table_A.col3 = 'cool'
选项1：使用内部联接：
UPDATE
A
SET
A.col1 = B.col1,
A.col2 = B.col2
FROM
Some_Table AS A
INNER JOIN Other_Table AS B
ON A.id = B.id
WHERE
A.col3 = 'cool'
选项2：共同相关子查询
UPDATE table
SET Col1 = B.Col1,
Col2 = B.Col2
FROM (
SELECT ID, Col1, Col2
FROM other_table) B
WHERE
B.ID = table.ID
单向
UPDATE t
SET t.col1 = o.col1,
t.col2 = o.col2
FROM
other_table o
JOIN
t ON t.id = o.id
WHERE
o.sql = 'cool'
Use:
drop table uno
drop table dos
create table uno
(
uid int,
col1 char(1),
col2 char(2)
)
create table dos
(
did int,
col1 char(1),
col2 char(2),
[sql] char(4)
)
insert into uno(uid) values (1)
insert into uno(uid) values (2)
insert into dos values (1,'a','b',null)
insert into dos values (2,'c','d','cool')
select * from uno
select * from dos
或者：
update uno set col1 = (select col1 from dos where uid = did and [sql]='cool'),
col2 = (select col2 from dos where uid = did and [sql]='cool')
OR:
update uno set col1=d.col1,col2=d.col2 from uno
inner join dos d on uid=did where [sql]='cool'
select * from uno
select * from dos
如果两个表中的ID列名相同，则只需将表名放在要更新的表之前，并为所选表使用别名，即：
update uno set col1 = (select col1 from dos d where uno.[id] = d.[id] and [sql]='cool'),
col2 = (select col2 from dos d where uno.[id] = d.[id] and [sql]='cool')
我会修改罗宾的优秀答案如下：
UPDATE Table
SET Table.col1 = other_table.col1,
Table.col2 = other_table.col2
FROM
Table
INNER JOIN other_table ON Table.id = other_table.id
WHERE
Table.col1 != other_table.col1
OR Table.col2 != other_table.col2
OR (
other_table.col1 IS NOT NULL
AND Table.col1 IS NULL
)
OR (
other_table.col2 IS NOT NULL
AND Table.col2 IS NULL
)
如果没有WHERE子句，您甚至会影响不需要受影响的行，这可能（可能）导致索引重新计算或触发真正不应该触发的触发器。
