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
以下解决方案适用于MySQL数据库：
UPDATE table1 a , table2 b
SET a.columname = 'some value'
WHERE b.columnname IS NULL ;
其他回答
UPDATE YourTable
SET Col1 = OtherTable.Col1,
Col2 = OtherTable.Col2
FROM (
SELECT ID, Col1, Col2
FROM other_table) AS OtherTable
WHERE
OtherTable.ID = YourTable.ID
另一种方法是使用派生表：
UPDATE t
SET t.col1 = a.col1
,t.col2 = a.col2
FROM (
SELECT id, col1, col2 FROM @tbl2) a
INNER JOIN @tbl1 t ON t.id = a.id
样本数据
DECLARE @tbl1 TABLE (id INT, col1 VARCHAR(10), col2 VARCHAR(10))
DECLARE @tbl2 TABLE (id INT, col1 VARCHAR(10), col2 VARCHAR(10))
INSERT @tbl1 SELECT 1, 'a', 'b' UNION SELECT 2, 'b', 'c'
INSERT @tbl2 SELECT 1, '1', '2' UNION SELECT 2, '3', '4'
UPDATE t
SET t.col1 = a.col1
,t.col2 = a.col2
FROM (
SELECT id, col1, col2 FROM @tbl2) a
INNER JOIN @tbl1 t ON t.id = a.id
SELECT * FROM @tbl1
SELECT * FROM @tbl2
下面是另一个有用的语法：
UPDATE suppliers
SET supplier_name = (SELECT customers.name
FROM customers
WHERE customers.customer_id = suppliers.supplier_id)
WHERE EXISTS (SELECT customers.name
FROM customers
WHERE customers.customer_id = suppliers.supplier_id);
它使用“WHERE EXIST”检查它是否为空。
Oracle SQL（使用别名）：
UPDATE Table T
SET T.col1 = (SELECT OT.col1 WHERE OT.id = T.id),
T.col2 = (SELECT OT.col2 WHERE OT.id = T.id);
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')
