Question

PLSQL游标批量更新数据问题

declare
C_YIBAOHAO ABB.YIBAOHAO%TYPE;
C_XINGMING ABB.XINGMING%TYPE;
C_DIQUHAO ABB.DIQUHAO%TYPE;

cursor mycursor IS select YIBAOHAO,XINGMING，DIQUHAO from ABB where ID=(select ID from BBB);

BEGIN
OPEN mycursor;
LOOP
FETCH mycursor INTO C_YIBAOHAO,C_XINGMING,C_DIQUHAO;
EXIT WHEN mycursor%NOTFOUND;

IF BBB.YIBAOHAO=C_YIBAOHAO and BBB.XINGMING=C_XINGMING THEN
UPDATE BBB SET DIQUHAO=C_DIQUHAO;
ELSIF BBB.YIBAOHAO=C_YIBAOHAO and BBB.DIQUHAO=C_DIQUHAO THEN
UPDATE BBB SET XINGMING=C_XINGMING;
ELSIF BBB.XINGMING=C_XINGMING and BBB.DIQUHAO=C_DIQUHAO THEN
UPDATE BBB SET YIBAOHAO=C_YIBAOHAO;
END IF;
END LOOP;

close mycursor;
end;
/
目的是，2表ABB,BBB的YIBAOHAO，XINGMING，DIQUHAO字段各自对比，若任意2字段的值相同，剩余另一字段的表BBB的值更新为表ABB该字段的值
是oracle的，主要是2表 对比更新

Answer 1

3个 UPDATE比开游标划算:

举其中一种情况的例子:

UPDATE BBB 
   SET BBB.DIQUHAO = (SELECT ABB.DIQUHAO FROM ABB WHERE ABB.ID = BBB.ID)
 WHERE EXISTS(SELECT 1 
                FROM ABB 
			   WHERE BBB.ID = ABB.ID  
                 AND ABB.XINGMING = BBB.XINGMING 
                 AND ABB.YIBAOHAO = BBB.YIBAOHAO);

Answer 2

两个问题：
1、在做update时，没有写条件，是要将BBB这个表的对应字段都更新成相同的么？
2、在判断语句中，直接引用BBB表字段的方法，可行么？

Answer 3

PLSQL游标批量更新数据问题
UPDATE BBB
SET BBB.DIQUHAO = (SELECT ABB.DIQUHAO FROM ABB WHERE ABB.ID = BBB.ID)
WHERE EXISTS(SELECT 1
FROM ABB
WHERE BBB.ID = ABB.ID
AND ABB.XINGMING = BBB.XINGMING
AND ABB.YIBAOHAO = BBB.YIBAOHAO);