oracle connect by prior

START with CONNECT by prior this syntax is primarily used to query the tree-structured relationships in a packet. What happens when you look at the raw data first? The first row of 1001 in the table is the parent of 1002, and the second row 1002 is the parent of 1003, so it loops. Title: Ask for one of the numbers to find its ultimate root node! How is it supposed to be done? Look at the SQL statement bel

Connect by prior start with is often used when a table has a recursive relationship. For example, we often store a complex directory tree in a table. You can also store some departments in a table, and these departments are affiliated with each other. In this case, you will use connect by prior start. The typical metho

In 10 Gb, Oracle provides a new pseudo column: connect_by_isleaf. This pseudo column can be used to determine whether the current record is a leaf node of the tree. This section describes how to implement the corresponding functions in 9i. First, construct an example: View plaincopy to clipboardprint?Create Table t_tree (ID number primary key, father_id number, name varchar2 (30 ));Insert into t_tree values (1, 0, 'A ');Insert into t_tree values (2, 1

START with CONNECT by prior this syntax is primarily used to query the tree-structured relationships in a packet. What happens when you look at the raw data first? The first row of 1001 in the table is the parent of 1002, and the second row 1002 is the parent of 1003, so it loops. Title: Ask for one of the numbers to find its ultimate root node! How is it supposed to be done? Look at the SQL statement bel

Select branchid from branch where parentbranchid = 'bra000000000000001' order by branchid The first statement can only query all the child nodes whose parent node is bra0000000000001. Select Br. branchidFrom branch brStart with Br. branchid = 'bra000000000000001'Connect by nocycle prior Br. branchid = Br. parentbranchid This statement can be used to identify all the child nodes whose parent node is braw.

For prior operations in a tree query, it is generally used in a connect by statement, and this prior operation is also available in the field list of select. Look at a simple example: Sql> CREATE TABLE T (ID number, parent_id number, name VARCHAR2 (30)); Table created. Sql> INSERT INTO t values (1, NULL, ' a '); 1 row created. Sql> INSERT INTO t values (2,

The SELECT statement in Oracle can implement a recursive query with the start With...connect by prior clause, which is used in structured queries, and its basic syntax is:Select ... from where Start with Connect by The data organization structure is shown below: The database table structure is as follows:CREATE TABLE

the full branches of Jones as the root node in the following waysSELECT substr (Sys_connect_by_path (ename, ', '), 3) EMPLOYEE from EMPwhere EMPNO not in (SELECT MGR from EMP WHERE MGR are not NULL) CONNECT by PRIOR Empno=mgr START with Ename= ' JONES ' EMPLOYEE------------------------------------------------------------ Jones->scott->adams Jones->ford->smith 2. Prior