用一张表更新另一张表
参考文献:https://www.cnblogs.com/kangkaii/p/8419088.html
1.方法1
update table1 set table1.val = (select val from table2 where table1.idd = table2.idd);
要是表1有表2没有,可能存在修改为空值的情况
2.方法1
update table1 set val = (select val from table2 where table1.idd = table2.idd)
where exists (select 1 from table2 where table1.idd = table2.idd)
要是表2有多条,会报错
3.方法1(远程报错/本地不报错)
merge into table1
using table2
on (table1.idd = table2.idd)
when matched then
update set table1.val = table2.val
要是表2有多条,会报错,但是报错情况和上面不一样,主要是不稳定
4.方法4(ok)
merge into table1
using (select t.idd ,max(t.val) m from table2 t group by t.idd)table2
on (table1.idd = table2.idd)
when matched then
update set table1.val = table2.m
完美
应用:解决会籍信息更新问题
操作步骤
0 备份
create table BI_TRADE_INFO_20190430 as select * from BI_TRADE_INFO;
1首先同步一下会员表,因为我发现有些人不在会员表中
2 然后将表导入到本地库 并导出sql语句(转储结构和数据),修改表空间为UGONGHUI 最后的sql语句如下
DROP TABLE "GONGHUI"."BI_TRADE_INFO_CHANGE";
CREATE TABLE "GONGHUI"."BI_TRADE_INFO_CHANGE" (
"ACCOUNT" VARCHAR2(255 CHAR) NULL ,
"NAME" VARCHAR2(255 CHAR) NULL ,
"TELE_PHONE" VARCHAR2(255 CHAR) NULL
)
LOGGING
NOCOMPRESS
NOCACHE
;
-- ----------------------------
-- Records of BI_TRADE_INFO_CHANGE
-- ----------------------------
INSERT INTO "GONGHUI"."BI_TRADE_INFO_CHANGE" VALUES ('00006472', 'xxx', 'xxxx');
INSERT INTO "GONGHUI"."BI_TRADE_INFO_CHANGE" VALUES ('00003490', 'xxxx', 'xxx');
INSERT INTO "GONGHUI"."BI_TRADE_INFO_CHANGE" VALUES ('00010263', 'xxx', 'xxx');
2.远程执行或者直接执行
@/root/BI_TRADE_INFO_CHANGE.sql
3.更新sql
merge into BI_TRADE_INFO bti
using (select btic.account ,max(btic.TELE_PHONE) TELE_PHONE from BI_TRADE_INFO_CHANGE btic group by btic.account) table2
on (bti.account = table2.account)
when matched then
update set bti.TELE_PHONE = table2.TELE_PHONE, bti.LEAGUER_TYPE = 1,bti.TRADE_STATUS=1
另外一张同理:
1.首先将表导入到本地库 并导出sql语句
2.在远程创建一张表
3.远程运行sql语句
4.更新
merge into BI_TRADE_INFO bti
using (select btic.account ,max(btic.TELE_PHONE) TELE_PHONE from BI_TRADE_INFO_CHANGE_NO btic group by btic.account) table2
on (bti.account = table2.account)
when matched then
update set bti.TELE_PHONE = table2.TELE_PHONE, bti.LEAGUER_TYPE = 2,bti.TRADE_STATUS=1