sql批量更新简单实例，有需要的朋友可以参考下。
先来看一个简单点的例子：
以下是更深一些的有关sql批量更新的讲解。
sql批量更新表时，特别是update一个表的列时，需要依赖另外的表，这种依赖可以是where条件子句，也可以是update的field的值依赖另外的表
一般有两种做法：
1）、使用存储过程
2）、在程序代码里逐条循环执行
本文为大家提供一种效率更高的批量更新SQL的方法，一句SQL即可替代麻烦的循环过程，分为MS SQLServer、Oracle、DB2三个库的版本。
复制代码 代码示例:
--关键点：t4和t1是同一个table，primary key肯定也是同一个，
--并以它进行关联，这样在 select语句里即可引用到要update的表的fields
UPDATE Table1 AS t1
SET (Field1,Field2) = (SELECT Field21, Field22
FROM Table2 t2
INNER JOIN Table3 t3
ON t3.Field31 = t2.Field23
INNER JOIN Table4 t4
ON t3.Field32 = t4.Filed41
WHERE t2.Field24 >= ''
AND t1.fId = t4.fId);
----------------------------MS SQLServer --------------------------------------
UPDATE t1
SET Field1 = Field21, Field2 = Field22
FROM Table2 t2
INNER JOIN Table3 t3
ON t3.Field31 = t2.Field23
INNER JOIN Table4 t4
ON t3.Field32 = t4.Filed41
WHERE ((t2.Field24 >= '')
AND t1.fId = t4.fId);
----------------------------Oracle --------------------------------------------
UPDATE Table1 t1
SET (Field1,Field2) = (SELECT Field21, Field22
FROM Table2 t2
INNER JOIN Table3 t3
ON t3.Field31 = t2.Field23
INNER JOIN Table4 t4
ON t3.Field32 = t4.Filed41
WHERE ((t2.Field24 >= '')
AND t1.fId = t4.fId))
WHERE EXISTS (SELECT Field21, Field22
FROM Table2 t2
INNER JOIN Table3 t3
ON t3.Field31 = t2.Field23
INNER JOIN Table4 t4
ON t3.Field32 = t4.Filed41
WHERE ((t2.Field24 >= '')
AND t1.fId = t4.fId));
---------------------------------DB2 ------------------------------------------
UPDATE Table1 AS t1
SET (Field1,Field2) = (SELECT Field21, Field22
FROM Table2 t2
INNER JOIN Table3 t3
ON t3.Field31 = t2.Field23
INNER JOIN Table4 t4
ON t3.Field32 = t4.Filed41
WHERE ((t2.Field24 >= '')
AND t1.fId = t4.fId))
WHERE EXISTS (SELECT Field21, Field22
FROM Table2 t2
INNER JOIN Table3 t3
ON t3.Field31 = t2.Field23
INNER JOIN Table4 t4
ON t3.Field32 = t4.Filed41
WHERE ((t2.Field24 >= '')
AND t1.fId = t4.fId));
