由一个表更新另一个表中field
来源:http://hi.baidu.com/chaowei_yuwen/blog/item/e2078ecbabccc081c9176841.html
由一个表里的数据更新另一个表里的数据：
情况：
因为操作错误，导致库存里件号和货品不符合，用新提供的excel数据(很多，而且仅仅批号lot_no和货品prod_id)去更新原有数据。
做法：
建立临时表(用临时表导数据是一种技巧)
SQL：
update inventory set prod_id=
(
select prod_id from inventory_temp where inventory_temp.lot_no=inventory.lot_no
)
where exists
(
select lot_no from inventory_temp where inventory_temp.lot_no=inventory.lot_no
)
体会：
用一个表去更新另一个表
上边写法可以简写为：
update a
set a.name=(select b.name from a.id = b.id)
where exsits (select 1 from a.id = b.id);
如果更新的是多个字段：
UPDATE employees a
SET department_id =
(SELECT department_id
FROM departments
WHERE location_id = '2100'),
(salary, commission_pct) =
(SELECT 1.1*AVG(salary), 1.5*AVG(commission_pct)
FROM employees b
WHERE a.department_id = b.department_id)
WHERE department_id IN
(SELECT department_id
FROM departments
WHERE location_id = 2900
OR location_id = 2700);
-------------------------------------------
另外一个: http://blog.csdn.net/Bobwu/archive/2009/01/13/3768636.aspx
1.
declare
cursor t1 is select * from tablename;
begin
for rec in t1 loop
update tablename t set t.detail=rec.jieshao where t.objectid=rec.objid;
end loop;
end;
2.
update student set (name,id )=
(select name ,id from (select student.rowid rd,student1.name,student1.id from student1,student where student1.int_id =student.int_id) tmp
where student.rowid=tmp.rd);
commit;
3.
update test_a a set (a.name,a.age)=
(select b.name,b.age from test_b b where a.id = b.id) where exists
(select * from test_b c where c.id=a.id)
4.
UPDATE t_A SET Djrq=
(
SELECT djrq FROM t_B WHERE t_A.ID = T_B.ID
WHERE ROWNUM = 1
)
WHERE t_A.ID IN
(
SELECT ID FROM t_B WHERE jwh='XX村'
)
5.
update tbl1 a
set (a.col1, a.col2) = (select b.col1, b.col2
from tbl2 b
where a.key = b.key)
where a.key in(select key from tbl2)
保存备用