DB2用一张表更新其他表的数据

表结构： CREATE TABLE ATEST  (ID    INTEGER,   NAME  VARCHAR(256),   CODE  INTEGER,   NAME2 VARCHAR(256)  )
CREATE TABLE BTEST  (ID    INTEGER,   CODE  INTEGER  )
CREATE TABLE CTEST  (ID    INTEGER,   NAME  VARCHAR(256),   NAME2 VARCHAR(256)  )
SQL语句： 一张表更新另一张表的字段： update atest set atest.name=(select ctest.name from ctest where atest.id = ctest.id) where atest.id in  (select ctest.id from ctest);

两张表关联更新另一张表的字段： update atest set (name,name2) = (SELECT CASE WHEN CTEST.NAME IS NULL THEN ATEST.NAME ELSE CTEST.NAME END, CASE WHEN CTEST.NAME2 IS NULL THEN ATEST.NAME2 ELSE CTEST.NAME2 END FROM BTEST LEFT JOIN CTEST on BTEST.ID = CTEST.ID  WHERE atest.CODE = BTEST.CODE) WHERE atest.CODE IN (SELECT BTEST.CODE FROM BTEST);
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)