Update MP SELECT Ancestors.md

Author: pchemguy

MP SELECT Ancestors.md

@@ -81,3 +81,38 @@ SELECT * FROM ancestors;
 ~~~
 
 Blocks *json_nodes* through *tops* constitute the same prologue as [before](select-desc#prologue). The *prefixes* block retrieves node prefixes from the *categories* table (alternatively, prefixes could be calculated from the input by stripping the last path parts). *json_prefixes* prepares "nested doll" JSON objects, and the *ancestors* block generates ancestor lists. The last block temporarily escapes any periods in names by replacing them with '^#^'  at the beginning and performing the inverse replacement at the end.
+
+A similar query splits provided paths directly:
+
+~~~sql
+WITH
+    json_nodes(ids) AS (
+        VALUES
+            ('["tcl/compat/zlib1/", "tcl/pkgs/thread2.8.7/tcl/cmdsrv/"]')
+    ), 
+    nodes AS (
+        SELECT "key" + 1 AS id, value AS node_id
+        FROM json_nodes AS jn, json_each(jn.ids) AS node_ids
+    ),
+    tops AS (SELECT id, node_id AS path FROM nodes),
+    levels AS (
+        SELECT id, path, length(path) - length(replace(path, '/', '')) AS depth
+        FROM tops
+    ),
+    json_objs AS (
+        SELECT *, json('{"' || replace(rtrim(path, '/'), '/', '": {"') ||
+            '":""' || replace(hex(zeroblob(depth)), '00', '}')) AS json_obj
+        FROM levels
+    ),
+    ancestors AS (
+        SELECT jo.id,
+            replace(replace(substr(fullkey, 3), '.', '/'), '^#^', '.') || '/' AS asc_path
+        FROM
+            json_objs AS jo,
+            json_tree(replace(jo.json_obj, '.', '^#^')) AS terms
+        WHERE terms.parent IS NOT NULL
+    )
+SELECT * FROM ancestors;
+~~~
+
+This query splits paths as provided and no longer accesses the *categories* table. The _nodes_ block also labels paths with array element id generated by _json_each_ instead of *ascii_id*.