Oracle-hierarchical statements-tree structure-show root nodes-not show root nodes

Oracle-hierarchical statements-tree structure-show root nodes-not show root nodes. the tree structure area_id of the Oracle-level statement is that the common primary key ID corresponds to parent_id .. administrative Division table 1. start with t. parent_id here is parent_id and does not display the top root node, so there will be multiple

[SQL] select t. * from HM_F_AREA t where length (t. area_id) = 6 start with t. parent_id = '2013' connect by t. parent_id = PRIOR t. area_id

 

2. start with t. id. If it is ID, the root is displayed, with only one root.

[SQL] select t. * from HM_F_AREA t where length (t. area_id) = 6 start with t. area_id = '000000' connect by t. parent_id = PRIOR t. area_id

 

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