Running SQL in Zerethon IDE

• Run (Ctrl/⌘+Enter) creates a new, empty in-memory SQLite database, runs every setup/*.sql file (sorted by name), imports data/*.csv, then runs the entry file — main.sql by default. Make another file the entry with the ▶ button next to it in the explorer.
• Results are tables (at most 200 rows shown each); statements that change data show how many rows they changed. The first error stops the run and shows the file and line.
• A statement is stopped after 5 seconds and a run after 10. There is one database per run: ATTACH, extensions and database files are not available, and it is never a real server.
• When a query fails with “no such table”, the editor offers to create a setup/ file for the missing tables.
• EXPLAIN QUERY PLAN SELECT … is shown as a tree, so you can see whether an index is used.
• Run tests (Ctrl/⌘+Shift+Enter) runs every test_*.sql file on its own fresh database (after setup/ and data/). A test file passes when none of its statements fails.

-- A failed check stops the file: the CHECK constraint rejects ok = 0.
CREATE TEMP TABLE checks (name TEXT NOT NULL, ok INTEGER NOT NULL CHECK (ok = 1));

INSERT INTO checks VALUES ('4 students', (SELECT count(*) = 4 FROM students));
INSERT INTO checks VALUES ('Linus has no courses',
    (SELECT count(*) = 0 FROM enrollments WHERE student_id = 4));

SELECT 'All ' || count(*) || ' checks passed.' AS result FROM checks;

Tip: Format uses sql-formatter with the SQLite dialect.