1)如果前导列选择性很好,后面的列条件是in,可能index access只有前导列,in的作为index filter,这时候不用inlist iterator算子。 2)如果前导列选择性不好,则会调用inlist iterator算子,转为多个索引区间扫描,这样in条件也会index access。 如果in条件是索引前导列,因为索引前导列要参与index access,所以基本都会采...
下面对这个sql进行inlist的查询转换: ops$admin@orcl>altersessionsetoptimizer_index_caching=100;delete/*+ use_concat*/fromtest twherecol1=:1andcol2in( :2, :3, :4, :5, :6, :7, :8, :9, :10, :11, :12, :13, :14, :15, :16, :17, :18, :19, :20, :21);---|Id|Operati...
RAW if the measure column is RAW; otherwise the return value is VARCHAR2. Aggregate Examples The following single-set aggregate example lists all of the employees in Department 30 in the hr.employees table, ordered by hire date and last name: SELECT LISTAGG(last_name, ‘; ‘) WITHIN GROUP ...
(username) from v$session where username is not null group by username; #当前连接数: select count(*) from v$process; #查询数据库锁表的语句 select sql_text from v$sql where hash_value in (select sql_hash_value from v$session where sid in (select session_id from v$locked_object)); #...
PL/SQLHome » Oracle Basics » Oracle IN Oracle INSummary: in this tutorial, you will learn how to use the Oracle IN operator to determine whether a value matches any value in a list or a subquery. Introduction to Oracle IN operator The Oracle IN operator determines whether a value mat...
(1) IN-List Iterator是IN后面是常量集合的首选方法。 (2) IN-List Iterator处理IN的前提条件,是IN所在的列上一定要有索引。 (3) 没有强制走IN-List Iterator的HINT,但可以通过联合设置10142和10157事件禁掉IN-List Iterator。 执行测试语句, SQL> select * from employees where department_id in (10,20,...
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方法1 找到以下注册表项。 然后,将 AllowInProcess (DWORD) 条目的值更改为 1。 此注册表项位于相应的提供程序名称下:HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSSQLServer\Providers\ProviderName。 方法2 按照以下步骤为使用 SQL Server Management Studio(SSMS)的提供程序设置“允许进程内”选项。
Protect databases against SQL injection attacks — including zero-day attacks —with SQL Firewall. Manage data across multiple regions while meeting data residency regulations using Globally Distributed Database with RAFT replication. Use the same technology whether your data lives on-premises or in Or...
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