Also, we can use a subquery with an IN operator in the WHERE clause. This is similar to the previous example that used the greater than operator for a single value. The IN operator can be applied to multiple values. Let’s say that the company wanted to update the price of some produc...
在UPDATE语句中,可以使用子查询(Subquery)来从其他表中检索数据并更新目标表。例如,如果需要更新employees表中的薪水,可以根据另一个表salary_info中的数据来更新: ```sql UPDATE employees e SET e.salary = (SELECT s.salary FROMsalary_info s WHERE e.id = s.id); ``` 通过使用子查询,可以实现更加灵活...
(query naming subquery_name); Retuning to our oversimplified example, let’s replace the temporary tables with the SQL “WITH” clause”:
SQL> insert into (select object_id,object_name,object_type from xgj where object_id<1000 WITH CHECK OPTION) 2 values(999,'xxx','xxxx'); 1. 2. 3. 4. 5. 6. 这样的语法看起来很特殊,其实是insert进subquery里的这张表里,只不过如果不满足subquery里的where条件的话,就不允许插入。 如果插入的...
7)SQL> insert into a values(6,(select dname from dept where deptno=10)); //values里的某列使用了subquery引用另一个表的数据。 注意: 1)insert语句会有约束的问题,不符合约束条件的insert不能成功。 2)default不但可以用于insert语句, 也可以用于update语句(考点) ...
语法： UPDATE 表名称 SET 列名称 = 新值 WHERE 列名称 = 某值 Person: LastNameFirstNameAddre...
The following statement has the same effect as the preceding example, but uses a subquery: DELETE FROM (SELECT * FROM emp) WHERE sal > 2000; To delete all rows from emp table. delete from emp; Merge Use the MERGE statement to select rows from one table for update or insertion into anot...
2.1 插入: Insert with a subquery method 这种方法就是使用insert 来实现。当然在创建分区表的时候可以一起插入数据,也可以创建好后在insert 进去。这种方法采用DDL语句,不产生UNDO,只产生少量REDO,建表完成后数据已经在分布到各个分区中。 SQL> select count(*) from dba; ...
2. Insert with a subquery method3. Partition exchange method4. DBMS_REDEFINITION详情参考How to Partition a Non-partitioned Table [ID 1070693.6]或者oracle将普通表改为分区表表分区的相关操作1.添加分区添加新的分区有 2 中情况:( 1)原分区里边界是 maxvalue 或者 default。 这种情况下,我们需要把边界...
Introduction to the Oracle subquery A subquery is a SELECT statement nested inside another statement such as SELECT, INSERT, UPDATE, or DELETE. Typically, you can use a subquery anywhere that you use an expression. Consider this following subquery example that uses the products table from the sam...