SQL-DDL与DML语句

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DML

数据操纵语言 Data Manipulation Language

insert

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insert into dept (deptno,dname,loc) values (50,'DEVELOPMENT','DETROIT');

update

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```

## delete
```sql

merge

从test2合并数据到test1表

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merge into test1 t1
using test2 t2
on (t1.deptno = t2.deptno)
when matched then
update set t1.dname=t2.dname,t1.loc=t2.loc
when not matched then
insert (deptno,dname,loc) values (t2.deptno,t2.dname,t2.loc);

oracle 锁

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select * from emp where empno=7890 for update;

DDL

drop/alter/