内容来自 oracle 11g 实用教程 郑阿奇等编
在 oracle 11g中有merge语句,用于根据与原表连接的结果,对目标表执行插入,更新,或者删除操作。例如,根据在一个表中找到的差异在另一个表中插入,更新或者删除行,这种方法可以对两个表进行信息同步。语法格式如下
merge into <目标表名>
using <原表名>on <条件表达式>
when matched then {update set ...|delete}
when not matched then insert(...) values()
merge into a
using xsb on (a.xh=xsb.学号)
when matched then update set a.xm = xsb.姓名,a.xb=xsb.性别,a.cssj = xsb.出生时间,a.zy=xsb.专业,a.zxf=xsb.总学分,a.bz=xsb.备注
when not matched then insert values(xsb.学号,xsb.姓名,xsb.性别,xsb.出生时间,xsb.专业,xsb.总学分,xsb.备注)
数据库
create table a ( XH char(6) not null primary key, xM char(8) not null, XB char(2) not null, CSSJ date not null, ZY char(24) null, ZXF number(2) null, BZ varchar(200) null );
-------------------------------------------------------- -- 文件已创建 - 星期日-七月-24-2016 -------------------------------------------------------- -------------------------------------------------------- -- DDL for Table XSB -------------------------------------------------------- CREATE TABLE "SCOTT"."XSB" ( "学号" CHAR(6 BYTE), "姓名" CHAR(8 BYTE), "性别" CHAR(2 BYTE) DEFAULT '男', "出生时间" DATE, "专业" CHAR(12 BYTE), "总学分" NUMBER(2,0), "备注" VARCHAR2(200 BYTE) ) SEGMENT CREATION IMMEDIATE PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS LOGGING STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT) TABLESPACE "USERS" ; REM INSERTING into SCOTT.XSB SET DEFINE OFF; Insert into SCOTT.XSB (学号,姓名,性别,出生时间,专业,总学分,备注) values ('151114','周何骏 ','男',to_date('25-9月 -98','DD-MON-RR'),'计算机 ',90,null); Insert into SCOTT.XSB (学号,姓名,性别,出生时间,专业,总学分,备注) values ('151101','王林 ','男',to_date('02-10月-97','DD-MON-RR'),'计算机 ',50,null); Insert into SCOTT.XSB (学号,姓名,性别,出生时间,专业,总学分,备注) values ('151103','王燕 ','女',to_date('10-6月 -96','DD-MON-RR'),'计算机 ',50,null); Insert into SCOTT.XSB (学号,姓名,性别,出生时间,专业,总学分,备注) values ('151202','王林 ','男',to_date('29-1月 -96','DD-MON-RR'),'通信工程 ',40,'有一门课不及格,待补考'); Insert into SCOTT.XSB (学号,姓名,性别,出生时间,专业,总学分,备注) values ('151108','林一帆 ','男',to_date('08-5月 -96','DD-MON-RR'),'计算机 ',52,'已提前修完一门课'); Insert into SCOTT.XSB (学号,姓名,性别,出生时间,专业,总学分,备注) values ('151204','马琳琳 ','女',to_date('02-10月-96','DD-MON-RR'),'通信工程 ',42,null); -------------------------------------------------------- -- DDL for Index SYS_C0011202 -------------------------------------------------------- CREATE UNIQUE INDEX "SCOTT"."SYS_C0011202" ON "SCOTT"."XSB" ("学号") PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT) TABLESPACE "USERS" ; -------------------------------------------------------- -- Constraints for Table XSB -------------------------------------------------------- ALTER TABLE "SCOTT"."XSB" MODIFY ("学号" NOT NULL ENABLE); ALTER TABLE "SCOTT"."XSB" MODIFY ("姓名" NOT NULL ENABLE); ALTER TABLE "SCOTT"."XSB" MODIFY ("性别" NOT NULL ENABLE); ALTER TABLE "SCOTT"."XSB" MODIFY ("出生时间" NOT NULL ENABLE); ALTER TABLE "SCOTT"."XSB" ADD PRIMARY KEY ("学号") USING INDEX PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT) TABLESPACE "USERS" ENABLE;