NLEVEL(t1.visible_path)-1 AS level,
COUNT(t2.*) AS children,
tutorial t2 ON (t1.visible_path = subpath(t2.visible_path, 0,-1) AND NOT t2.is_deleted AND t2.is_public)
NOT t1.is_deleted AND t1.is_public
t1.visible_path USING <
ERROR: could not write block 1 of temporary file: No space left on device
HINT: Perhaps out of disk space?