What is Oracle SQL connect by level?

Another question is: What is level in Oracle SQL

Definition: The term LEVEL is a pseudocolumn that Oracle PL/SQL uses to identify the hierarchy level using a numeric format. The LEVEL pseudocolumn returns one row for each hierarchical query. Two rows for each child of a root are returned.

What is connect by in Oracle? CONNECTBY is used to indicate the relationship between parent and child rows in the hierarchy. The NOCYCLE parameter tells Oracle Database that CONNECT By LOOP does not exist in the query. This parameter can be used in conjunction with the CONNECT_BY_ISCYCLE pseudocolumn for identifying rows that contain the loop.

People often ask what connects to them.

"Connect by" describes how to walk between the parent nodes and children. It is easiest to use emp as an example. Start with "where mgr IS NULL", and you will get the set of employees without mgr (they are at the top of the tree). If we. CONNECT BY PREVIOUS EMPNO = * current */ MGR.

What is recursive SQL?

A recursive question is one that refers back to itself. Different DBMS products implement recursive SQL in different ways. Recursion can be implemented in standard SQL99 using common table expressions, (CTEs). DB2, Microsoft SQL Server, Oracle, and PostgreSQL all support recursive query using CTEs.