求解一个update语句 A表: a1,a2,a3,a4 B表:b1,b2,b3,b4现在需要当a2=b2时,把b3的值给a3,把b4的值给a4. 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 UPDATE A SET A.a3 = B.b3,A.a4=B.b4FROM A JOIN B ON A.a2 = B.b2 SQL codeUPDATE A SET A.a3 = B.b3,A.a4=B.b4FROM A , B where A.a2 = B.b2 UPDATE A SET A.a3 = B.b3,A.a4=B.b4FROM A JOIN B ON A.a2 = B.b2 update a set a.a3=b.b3,a.a4=b.b4 from a join b on A.a2 = B.b2 而且如果后面还有where,要怎么写啊,比如B.b4>100 UPDATE A SET A.a3 = B.b3,A.a4=B.b4FROM B where A.a2 = B.b2 UPDATE A SET A.a3 = B.b3,A.a4=B.b4FROM A JOIN B ON A.a2 = B.b2 WHERE B.b4>100 UPDATE A SET A.a3 = B.b3,A.a4=B.b4FROM A JOIN B ON A.a2 = B.b2 and B.b4>100不就行了 UPDATE A SET A.a3 = B.b3,A.a4=B.b4FROM A JOIN B ON A.a2 = B.b2 where B.b4>100 又是一道抢答题啊? update ...from ,如果数据量比较大的时候,可以在a2和b2上建立索引. 如果修改的数量超过全表的20%!建立索引也可能走scan而不走seek! 求写一函数 数据库转换 sql查询问题!! 尊敬的邹老师:看看分页的存储过程 IBM服务器Xeon2.8cpu,1G内存,SQLserver2000。在SQL中有个数据表有144万记录,在SQL的查询分析器中用条件为“where year(日期数据列)=20 DST的问题 怎么在sql2000里加图片啊? 请教动态sql语句过长的解决方法 累加字符型字段 VFP 6.0 编译成EXE文件后执行后一闪即消失如何解决。急 存储过程中SQL语句拼接问题 VB6做的登录界面重新编译后怎么提示密码错误?谢谢!
UPDATE A SET A.a3 = B.b3,A.a4=B.b4
FROM A JOIN B ON A.a2 = B.b2
UPDATE A SET A.a3 = B.b3,A.a4=B.b4
FROM A , B
where A.a2 = B.b2
FROM A JOIN B ON A.a2 = B.b2
from a join b on A.a2 = B.b2
FROM B where A.a2 = B.b2
FROM A JOIN B ON A.a2 = B.b2 WHERE B.b4>100
UPDATE A SET A.a3 = B.b3,A.a4=B.b4
FROM A JOIN B ON A.a2 = B.b2 and B.b4>100
不就行了
FROM A JOIN B ON A.a2 = B.b2
where B.b4>100