In this Oracle SQL query example, you will learn how to get the hierarchical tree from the table data.
The below example is given on the
EMP table of the
SCOTT schema. Below is the screenshot of the data:
Oracle SQL Query to Get Hierarchical Tree Data of EMP Table
I assume you requiring a hierarchical tree query to use in the Oracle Forms or in the Oracle Apex application. If yes then the below SQL query example is for you:
SELECT CASE WHEN CONNECT_BY_ISLEAF = 1 THEN 0 WHEN LEVEL = 1 THEN 1 ELSE - 1 END AS STATUS, LEVEL, ENAME AS TITLE, 'icon-tree-folder' AS ICON, EMPNO AS VALUE, ENAME AS TOOLTIP, '#' AS LINK FROM EMP START WITH MGR IS NULL CONNECT BY PRIOR EMPNO = MGR ORDER SIBLINGS BY ENAME