--- title: "parse_path" slug: "dev-database-reference-sql-functions-string-parse-path" updated: 2026-10-30T18:18:56Z published: 2026-10-30T18:18:56Z canonical: "docs.vastdata.com/dev-database-reference-sql-functions-string-parse-path" --- > ## Documentation Index > Fetch the complete documentation index at: https://docs.vastdata.com/llms.txt > Use this file to discover all available pages before exploring further. # parse_path *Applies to VAST Cluster 5.5.* *[Functions](/develop/docs/dev-database-reference-sql-functions-index) › [Text basics](/develop/docs/dev-database-reference-sql-functions-string-text-basics) › Paths.* Splits a file path into a list of its components: the directories, then the file name. By default both `/` and `\` separate components. It has no aliases. ## Syntax ``` parse_path(path) parse_path(path, separator) ``` | Argument | Type | Description | | --- | --- | --- | | `path` | `VARCHAR` | The path to split. | | `separator` | `VARCHAR` | Optional. Which character separates components: `'forward_slash'`, `'backslash'`, `'both_slash'` (the default) or `'system'`, in lower case. Any other value, and `NULL`, splits as `'both_slash'` does. See [What it does](/develop/docs/dev-database-reference-sql-functions-string-parse-path#what-it-does). | **Returns:** `VARCHAR[]`, a list of strings (a Python list in the driver's results). **Aliases:** none. ## Set up the examples The examples connect with the ADBC driver, as in [VAST Query Engine (ADBC)](/develop/docs/dev-database-integrations-adbc), and work in a schema called `docs_sql_fn_parse_path`. Set `QE_ENDPOINT`, `AWS_ACCESS_KEY_ID`, `AWS_SECRET_ACCESS_KEY` and `VASTDB_BUCKET` ([SQL reference](/develop/docs/dev-database-reference-sql-index#example-connect-and-use-a-transaction)), and run the blocks in order in one Python session. Below each block is the output you should see. This block connects, defines the `run()` and `plan()` helpers, and creates a table of five file paths, with the number of components stored next to each path. One path is a Windows path and one ends with a separator; the last row has no values: ``` import os import re import adbc_driver_manager import adbc_driver_manager.dbapi as dbapi import adbc_driver_vastdb BUCKET = os.environ["VASTDB_BUCKET"] SCHEMA = f'"{BUCKET}/docs_sql_fn_parse_path"' conn = dbapi.connect( driver=adbc_driver_vastdb.get_driver_path(), db_kwargs={ "vast.db.endpoint": os.environ["QE_ENDPOINT"], "vast.db.access_key": os.environ["AWS_ACCESS_KEY_ID"], "vast.db.secret_key": os.environ["AWS_SECRET_ACCESS_KEY"], }, autocommit=True, ) def server_message(e): """The server's message in a driver error, without the request ID or the echoed statement.""" text = re.sub(r"\[req=0x[0-9a-f]+\]: ", "", str(e)) found = (re.search(r'message: "(.*?)", request_id', text, re.S) or re.search(r"description: (.*)\)", text, re.S)) message = found.group(1) if found else text.strip().splitlines()[-1] message = re.sub(r"^Plan query: '.*?' failed with: ", "", message, flags=re.S) message = re.split(r"\\n|\n", message)[0].replace('\\"', '"') return message.replace(BUCKET, "") def run(sql): """Run one statement. Print the rows it returns, or the error.""" try: with conn.cursor() as cur: cur.execute(sql) rows = cur.fetchall() if cur.description else [] except (adbc_driver_manager.Error, OSError) as e: print(f"{type(e).__name__}: {server_message(e)}") else: print(rows) def plan(sql): """Print the plan without its ~N Rows lines: the table's row count, which can still be 0 just after an insert.""" with conn.cursor() as cur: cur.execute("EXPLAIN " + sql) steps = cur.fetchall()[0][1] print("\n".join(line for line in steps.splitlines() if "Rows" not in line)) TABLE = f"{SCHEMA}.files" run(f"CREATE SCHEMA IF NOT EXISTS {SCHEMA}") run(f"CREATE TABLE IF NOT EXISTS {TABLE} (id BIGINT, path VARCHAR, depth BIGINT)") run(f"INSERT INTO {TABLE} VALUES " "(1, '/data/logs/app.log', 4), " "(2, '/home/ada/projects/notes.tar.gz', 5), " "(3, 'C:\\Users\\jose\\poems.docx', 4), " "(4, 'exports/2026/', 2), " "(5, NULL, NULL)") ``` ``` [] [] [(5,)] ``` ## What it does `parse_path` splits the path at each separator and returns the parts in order: | Path | Result | Why | | --- | --- | --- | | `'/data/logs/app.log'` | `['/', 'data', 'logs', 'app.log']` | A leading `/` (the root) is its own first component. | | `'C:\dir\file.tar.gz'` | `['C:', 'dir', 'file.tar.gz']` | By default `\` is a separator too. A drive letter such as `C:` is an ordinary component. | | `'a/b/'` | `['a', 'b']` | A trailing separator adds no empty component. | | `'/a//b/'` | `['/', 'a', 'b']` | Repeated separators add no empty component either. | | `'/'` | `['/']` | The root alone. | | `'\a\\b'` | `['\', 'a', 'b']` | A leading `\` is the root too, and the doubled `\` adds no empty component. | | `'\\server\share\f'` | `['\', 'server', 'share', 'f']` | The two leading backslashes of a network (UNC) path become a single `\` root component. | | `''` | `[]` | An empty path gives an empty list. | **The separator argument.** Without it, `/` and `\` both separate components, as with `'both_slash'`. `'forward_slash'` splits only on `/`, and `'backslash'` only on `\`; the other character is then part of a component. On the cluster, `'system'` splits only on `/`, like `'forward_slash'`: | Call | Result | | --- | --- | | `parse_path('a/b\c')` | `['a', 'b', 'c']` | | `parse_path('a/b\c', 'both_slash')` | `['a', 'b', 'c']` | | `parse_path('a/b\c', 'forward_slash')` | `['a', 'b\c']` | | `parse_path('a/b\c', 'system')` | `['a', 'b\c']` | | `parse_path('a/b\c', 'backslash')` | `['a/b', 'c']` | | `parse_path('a/b\c', 'x')` | `['a', 'b', 'c']`: a value that isn't a separator name is accepted without an error and splits on both. | | `parse_path('a/b', NULL)` | `['a', 'b']`: a `NULL` separator doesn't make the result `NULL`; it splits on both. | The names are case-sensitive: `parse_path('a/b', 'BACKSLASH')` returns `['a', 'b']`, because `'BACKSLASH'` isn't recognised and both characters separate. Because an unknown or misspelt name (`'BACKSLASH'`, `'backslashes'`, `'forward'`) isn't an error, it goes unnoticed. Check the spelling against the list above. In Python code, write each `\` of a path as `\\` inside the string (`"parse_path('a/b\\c')"`), so that the SQL receives one backslash. Python also prints each backslash in the results doubled: `'b\\c'` is the three-character string `b\c`. ## NULLs and edge cases | Input | Result | | --- | --- | | `NULL` | `NULL` | | `''` (empty string) | `[]` | | `'/'` | `['/']` | | `'/a//b/'` | `['/', 'a', 'b']` | | `'a/b'` with separator `NULL` | `['a', 'b']` | | `'a/b'` with separator `'x'` | `['a', 'b']` | | `'a/b\c'` with no separator | `['a', 'b', 'c']` | | `'a/b\c'` with `'forward_slash'` | `['a', 'b\c']` | | `'a/b\c'` with `'backslash'` | `['a/b', 'c']` | | `'a/b\c'` with `'both_slash'` | `['a', 'b', 'c']` | | `'a/b\c'` with `'system'` | `['a', 'b\c']` | | `'a/b\c'` with `'x'` | `['a', 'b', 'c']` | | A number, decimal, date, boolean, `BLOB` or list | Error: `No function matches the given name and argument types` | The same cases, as the cluster returns them. The third and fourth lines run every separator mode on a path with both separators; Python prints `b\c` as `'b\\c'`. They use the table and helpers from [Set up the examples](/develop/docs/dev-database-reference-sql-functions-string-parse-path#set-up-the-examples): ``` run("SELECT parse_path(NULL), parse_path(''), parse_path('/'), parse_path('/a//b/')") run("SELECT parse_path('a/b', NULL), parse_path('a/b', 'x')") run("SELECT parse_path('a/b\\c'), parse_path('a/b\\c', 'forward_slash'), parse_path('a/b\\c', 'backslash')") run("SELECT parse_path('a/b\\c', 'both_slash'), parse_path('a/b\\c', 'system'), parse_path('a/b\\c', 'x')") run("SELECT parse_path(123)") ``` ``` [(None, [], ['/'], ['/', 'a', 'b'])] [(['a', 'b'], ['a', 'b'])] [(['a', 'b', 'c'], ['a', 'b\\c'], ['a/b', 'c'])] [(['a', 'b', 'c'], ['a', 'b\\c'], ['a', 'b', 'c'])] InternalError: Binder Error: No function matches the given name and argument types 'parse_path(INTEGER_LITERAL)'. You might need to add explicit type casts. ``` ## Examples The components of each path, and how many there are: ``` run(f"SELECT id, parse_path(path), length(parse_path(path)) FROM {TABLE} ORDER BY id LIMIT 10") ``` ``` [(1, ['/', 'data', 'logs', 'app.log'], 4), (2, ['/', 'home', 'ada', 'projects', 'notes.tar.gz'], 5), (3, ['C:', 'Users', 'jose', 'poems.docx'], 4), (4, ['exports', '2026'], 2), (5, None, None)] ``` The same paths split only on `/`. The Windows path stays in one piece: ``` run(f"SELECT id, parse_path(path, 'forward_slash') FROM {TABLE} ORDER BY id LIMIT 10") ``` ``` [(1, ['/', 'data', 'logs', 'app.log']), (2, ['/', 'home', 'ada', 'projects', 'notes.tar.gz']), (3, ['C:\\Users\\jose\\poems.docx']), (4, ['exports', '2026']), (5, None)] ``` Keep only the paths with at least five components: ``` run(f"SELECT id, path FROM {TABLE} WHERE length(parse_path(path)) >= 5 ORDER BY id LIMIT 10") ``` ``` [(2, '/home/ada/projects/notes.tar.gz')] ``` ## How it runs in VAST The Query Engine runs on the cluster's CNodes, and a query on a table starts with a scan in VAST DataBase (`VAST_SCAN`). VAST DataBase can evaluate a comparison of a column with a constant, but not a function of a column, so `parse_path()` is always computed by the Query Engine: - **In the `SELECT` list,** the scan reads the column and the Query Engine computes `parse_path()` for each row it returns. - **In `WHERE`,** the scan sends the column for every row, and a `FILTER` step in the Query Engine computes `parse_path()` and keeps the rows that match. No rows are skipped in storage. The plan of the `WHERE` example shows the `FILTER` step above the scan: ``` plan(f"SELECT id FROM {TABLE} WHERE length(parse_path(path)) >= 5") ``` ``` ┌───────────────────────────┐ │ PROJECTION │ │ ──────────────────── │ │ #1 │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ FILTER │ │ ──────────────────── │ │ (length(parse_path(path)) │ │ >= 5) │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ │ │ Projections: │ │ path │ │ id │ │ │ └───────────────────────────┘ ``` ## Make it faster - **Store the part you filter on.** If you filter on a path's depth, its top-level directory or its file name, compute it when you write the rows and keep it in its own column. A comparison of a raw column with a constant is pushed down to VAST DataBase, so rows that don't match never leave storage. The plan for `depth >= 5` has no `FILTER` step: ``` plan(f"SELECT id FROM {TABLE} WHERE depth >= 5") ``` ``` ┌───────────────────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ Projections: id │ │ │ └───────────────────────────┘ ``` - **Combine it with a pushed-down condition.** In `id > 100 AND length(parse_path(path)) >= 5`, `id > 100` is still evaluated in VAST DataBase, so `parse_path()` runs only on the rows that pass it. ## Limitations and errors - **Strings only.** A number, a decimal, a date, a boolean, a `BLOB` or a list fails with `No function matches the given name and argument types`. - **Unknown separator names aren't errors.** A value other than the lower-case mode names (an upper-case `'BACKSLASH'` included) is accepted, and so is `NULL`; both split on `/` and `\`. See [What it does](/develop/docs/dev-database-reference-sql-functions-string-parse-path#what-it-does). - **`'system'` means `/` on the cluster.** Use `'backslash'` or the default for Windows paths. - **Empty components are dropped.** `'/a//b/'` gives `['/', 'a', 'b']`: the doubled and trailing separators are gone, so you can't always rebuild the original string from the list. ``` run("SELECT parse_path('\\xAA'::BLOB)") run("SELECT parse_path(['a', 'b'])") ``` ``` InternalError: Binder Error: No function matches the given name and argument types 'parse_path(BLOB)'. You might need to add explicit type casts. InternalError: Binder Error: No function matches the given name and argument types 'parse_path(VARCHAR[])'. You might need to add explicit type casts. ``` ## Similar functions | Function | Returns | Result for `'/home/ada/notes.txt'` | | --- | --- | --- | | `parse_path` | every component, as a list | `['/', 'home', 'ada', 'notes.txt']` | | [parse_dirname](/develop/docs/dev-database-reference-sql-functions-string-parse-dirname) | the top-level directory | `'/'` | | [parse_dirpath](/develop/docs/dev-database-reference-sql-functions-string-parse-dirpath) | the path without its last component | `'/home/ada'` | | [parse_filename](/develop/docs/dev-database-reference-sql-functions-string-parse-filename) | the last component | `'notes.txt'` | | [parse_filename](/develop/docs/dev-database-reference-sql-functions-string-parse-filename) with `trim_extension` true | the last component without its last extension | `'notes'` | To split a string on a separator of your choice instead, see [string_split](/develop/docs/dev-database-reference-sql-functions-string-string-split). ``` run("SELECT parse_path('/home/ada/notes.txt'), parse_dirname('/home/ada/notes.txt'), parse_dirpath('/home/ada/notes.txt'), " "parse_filename('/home/ada/notes.txt'), parse_filename('/home/ada/notes.txt', true)") ``` ``` [(['/', 'home', 'ada', 'notes.txt'], '/', '/home/ada', 'notes.txt', 'notes')] ``` Clean up: ``` run(f"DROP TABLE IF EXISTS {TABLE}") run(f"DROP SCHEMA IF EXISTS {SCHEMA}") conn.close() ``` ``` [] [] ``` ## See also - [Text basics](/develop/docs/dev-database-reference-sql-functions-string-text-basics): all the text functions. - [parse_dirname](/develop/docs/dev-database-reference-sql-functions-string-parse-dirname), [parse_dirpath](/develop/docs/dev-database-reference-sql-functions-string-parse-dirpath) and [parse_filename](/develop/docs/dev-database-reference-sql-functions-string-parse-filename): one part of a path. - [Where filters run](/develop/docs/dev-database-reference-sql-select#where-filters-run) and [pushdowns](/develop/docs/dev-database-reference-pushdowns). - [EXPLAIN](/develop/docs/dev-database-reference-sql-explain): how to read a plan.