menu_book Course Curriculum (PostgreSQL Complete Course) expand_more
EXPLAIN
Learn EXPLAIN in PostgreSQL through the exact construct, a dedicated example, a boundary case, and a mastery check.
EXPLAIN is an atomic PostgreSQL lesson inside Administration & Performance. 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 EXPLAIN rather than on generic PostgreSQL syntax.
Topic-specific example
EXPLAIN (COSTS true) SELECT id,email FROM users WHERE email='a@example.com';
Test EXPLAIN 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.