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Oracle SQL Complete Course / Hierarchical & Analytic SQL

LEVEL pseudocolumn

Learn LEVEL pseudocolumn in Oracle SQL through the exact construct, a dedicated example, a boundary case, and a mastery check.

10 min read • Intermediate

LEVEL pseudocolumn is an atomic Oracle SQL lesson inside Hierarchical & Analytic SQL. The example uses the specific syntax, command, API, instruction, or language rule named by this lesson.

Study the construct itself, then change one relevant input and predict the result before running it. That keeps this lesson focused on LEVEL pseudocolumn rather than on generic Oracle SQL syntax.

Topic-specific example

oraclesql-03-03.sql
sql Try It Live 
SELECT LEVEL AS depth,employee_id FROM employees START WITH manager_id IS NULL CONNECT BY PRIOR employee_id=manager_id;
Edge case / engineering note

Test LEVEL pseudocolumn with an empty result, NULL/missing value, duplicate key, or concurrent operation where relevant; database behavior should be verified at the boundary shown by this example.

Content source & attribution
Original Syntaxis Content · Original Syntaxis Content

Lesson quizzes

LEVEL pseudocolumn Mastery Check →
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