使用别名：

UPDATE t
   SET t.col1 = o.col1
  FROM table1 AS t
         INNER JOIN 
       table2 AS o 
         ON t.id = o.id

我以前使用过INSERT SELECT。对于那些想使用新东西的人来说，这里有一个类似的解决方案，但它要短得多：

UPDATE table1                                          // Table that's going to be updated.
LEFT JOIN                                              // Type of join.
    table2 AS tb2                                      // Second table and rename for easy.
ON
    tb2.filedToMatchTables = table1.fieldToMatchTables // Fields to connect both tables.
SET
    fieldFromTable1 = tb2.fieldFromTable2;             // Field to be updated on table1.

    field1FromTable1 = tb2.field1FromTable2,           // This is in the case you need to
    field1FromTable1 = tb2.field1FromTable2,           // update more than one field.
    field1FromTable1 = tb2.field1FromTable2;           // Remember to put ; at the end.

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

通过CTE进行更新比此处的其他答案更具可读性：

;WITH cte
     AS (SELECT col1,col2,id
         FROM   other_table
         WHERE  sql = 'cool')
UPDATE A
SET    A.col1 = B.col1,
       A.col2 = B.col2
FROM   table A
       INNER JOIN cte B
               ON A.id = B.id

我添加这个只是为了让你可以看到一个快速的方法来编写它，这样你就可以在更新之前检查将要更新的内容。

UPDATE Table 
SET  Table.col1 = other_table.col1,
     Table.col2 = other_table.col2 
--select Table.col1, other_table.col,Table.col2,other_table.col2, *   
FROM     Table 
INNER JOIN     other_table 
    ON     Table.id = other_table.id 

另一种尚未提及的可能性是将SELECT语句本身放入CTE，然后更新CTE。

WITH CTE
     AS (SELECT T1.Col1,
                T2.Col1 AS _Col1,
                T1.Col2,
                T2.Col2 AS _Col2
         FROM   T1
                JOIN T2
                  ON T1.id = T2.id
         /*Where clause added to exclude rows that are the same in both tables
           Handles NULL values correctly*/
         WHERE EXISTS(SELECT T1.Col1,
                             T1.Col2
                       EXCEPT
                       SELECT T2.Col1,
                              T2.Col2))
UPDATE CTE
SET    Col1 = _Col1,
       Col2 = _Col2;

这样做的好处是，首先很容易单独运行SELECT语句来检查结果的完整性，但如果源表和目标表中的列名称相同，则需要如上所述对列进行别名。

这也具有与专有UPDATE相同的限制。。。其他四个答案中显示了FROM语法。如果源表位于一对多连接的多方，则无法确定更新中将使用哪些可能匹配的连接记录（如果多次尝试更新同一行，MERGE会通过引发错误来避免此问题）。