--- title: "generate_series" slug: "dev-database-reference-sql-functions-lists-generate-series" updated: 2026-10-30T18:19:06Z published: 2026-10-30T18:19:06Z canonical: "docs.vastdata.com/dev-database-reference-sql-functions-lists-generate-series" --- > ## 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. # generate_series *Applies to VAST Cluster 5.5.* *[Functions](/develop/docs/dev-database-reference-sql-functions-index) › [List, struct and map functions](/develop/docs/dev-database-reference-sql-functions-lists-and-structs) › Build a list.* Returns a list of integers, or of timestamps, from `start` up to and including `stop`, `step` apart. [range](/develop/docs/dev-database-reference-sql-functions-lists-range) is the same but stops before `stop`. In `FROM`, `generate_series` returns rows instead of a list: see [table functions](/develop/docs/dev-database-reference-sql-functions-table-functions). ## Syntax ``` generate_series(stop) generate_series(start, stop) generate_series(start, stop, step) generate_series(start_ts, stop_ts, interval) ``` | Argument | Type | Description | | --- | --- | --- | | `start` | `BIGINT` (any integer) | The first value. Leave it out to start at 0. | | `stop` | `BIGINT` (any integer) | The last value. It's in the list if the steps reach it. | | `step` | `BIGINT` (any integer) | The distance between values; negative to count down. Default 1. | | `start_ts`, `stop_ts` | `TIMESTAMP` (a `DATE` is converted) | The first and the last timestamp. | | `interval` | `INTERVAL` | The distance between timestamps. Required for timestamps. | **Returns:** `BIGINT[]` for integers, `TIMESTAMP[]` for timestamps. ## 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_lists_generate_series`. 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 four print jobs, each with a first and last page and a start time. In the third the last page is before the first, and 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_lists_generate_series"' 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}.jobs" run(f"CREATE SCHEMA IF NOT EXISTS {SCHEMA}") run(f"CREATE TABLE IF NOT EXISTS {TABLE} (id BIGINT, first_page BIGINT, last_page BIGINT, started TIMESTAMP)") run(f"INSERT INTO {TABLE} VALUES " "(1, 1, 4, TIMESTAMP '2026-03-28 12:00:00'), " "(2, 5, 5, TIMESTAMP '2026-01-31 00:00:00'), " "(3, 9, 6, TIMESTAMP '2026-10-01 08:30:00'), " "(4, NULL, NULL, NULL)") ``` ``` [] [] [(4,)] ``` ## What it does `generate_series` counts from `start` (0 if you leave it out) by `step` (1 if you leave it out), and includes `stop` if a step lands on it: | Call | Result | | --- | --- | | `generate_series(5)` | `[0, 1, 2, 3, 4, 5]` | | `generate_series(1, 5)` | `[1, 2, 3, 4, 5]` | | `generate_series(1, 10, 3)` | `[1, 4, 7, 10]` | | `generate_series(5, 1, -2)` | `[5, 3, 1]` | | `generate_series(-2, 2)` | `[-2, -1, 0, 1, 2]` | `generate_series(4)` has five elements, not four: it starts at 0 and includes 4. To stop before `stop`, use [range](/develop/docs/dev-database-reference-sql-functions-lists-range). **Timestamps.** With two timestamps and an `INTERVAL`, `generate_series` returns the timestamps from `start_ts` to `stop_ts`, `interval` apart, both ends included. A `DATE` is converted to a `TIMESTAMP` at midnight, so the result is a `TIMESTAMP[]`. A month step is added to the previous value: from January 31, `INTERVAL 1 MONTH` gives February 28, then March 28, April 28 and May 28. ## NULLs and edge cases | Input | Result | | --- | --- | | Any argument NULL | `NULL` | | `generate_series(0)` | `[0]` | | `generate_series(-3)` | `[]` | | `generate_series(5, 5)` | `[5]` | | `generate_series(5, 1)` | `[]` (stop is before start) | | `generate_series(1, 5, -1)` | `[]` (the step goes away from stop) | | `generate_series(1, 5, 0)` | `[]` (a zero step isn't an error) | | `generate_series(0, 10, 20)` | `[0]` | | `generate_series('1', '3')` | `[1, 2, 3]` (a numeric string is converted) | | `generate_series(TIMESTAMP '2026-01-01', TIMESTAMP '2026-01-03', INTERVAL 0 DAY)` | `[]` | | `generate_series(1.5)`, `generate_series(true)`, `generate_series(DATE '2026-10-16')` | Error: `No function matches the given name and argument types` | | Two timestamps without an interval | Error: `No function matches the given name and argument types 'generate_series(TIMESTAMP, TIMESTAMP)'` | The same cases, as the cluster returns them. They use the table and helpers from [Set up the examples](/develop/docs/dev-database-reference-sql-functions-lists-generate-series#set-up-the-examples): ``` run("SELECT generate_series(NULL), generate_series(1, NULL), generate_series(1, 5, NULL), generate_series(0), " "generate_series(-3), generate_series(5, 5), generate_series(5, 1)") run("SELECT generate_series(1, 5, -1), generate_series(1, 5, 0), generate_series(0, 10, 20), generate_series('1', '3')") run("SELECT generate_series(TIMESTAMP '2026-01-01', TIMESTAMP '2026-01-03', INTERVAL 0 DAY)") run("SELECT generate_series(1.5)") run("SELECT generate_series(TIMESTAMP '2026-01-01', TIMESTAMP '2026-01-03')") ``` ``` [(None, None, None, [0], [], [5], [])] [([], [], [0], [1, 2, 3])] [([],)] InternalError: Binder Error: No function matches the given name and argument types 'generate_series(DECIMAL(2,1))'. You might need to add explicit type casts. InternalError: Binder Error: No function matches the given name and argument types 'generate_series(TIMESTAMP, TIMESTAMP)'. You might need to add explicit type casts. ``` ## Examples The pages of each job, first and last included. Job 3 gets an empty list, and job 4 gets NULL: ``` run(f"SELECT id, generate_series(first_page, last_page) FROM {TABLE} ORDER BY id LIMIT 10") ``` ``` [(1, [1, 2, 3, 4]), (2, [5]), (3, []), (4, None)] ``` The start of each of the first three days of a job (the start and two days later, both included), and a month-by-month list from January 31: ``` run(f"SELECT id, generate_series(started, started + INTERVAL 2 DAY, INTERVAL 1 DAY) FROM {TABLE} ORDER BY id LIMIT 10") run("SELECT generate_series(TIMESTAMP '2026-01-31', TIMESTAMP '2026-05-31', INTERVAL 1 MONTH)") ``` ``` [(1, [datetime.datetime(2026, 3, 28, 12, 0), datetime.datetime(2026, 3, 29, 12, 0), datetime.datetime(2026, 3, 30, 12, 0)]), (2, [datetime.datetime(2026, 1, 31, 0, 0), datetime.datetime(2026, 2, 1, 0, 0), datetime.datetime(2026, 2, 2, 0, 0)]), (3, [datetime.datetime(2026, 10, 1, 8, 30), datetime.datetime(2026, 10, 2, 8, 30), datetime.datetime(2026, 10, 3, 8, 30)]), (4, None)] [([datetime.datetime(2026, 1, 31, 0, 0), datetime.datetime(2026, 2, 28, 0, 0), datetime.datetime(2026, 3, 28, 0, 0), datetime.datetime(2026, 4, 28, 0, 0), datetime.datetime(2026, 5, 28, 0, 0)],)] ``` Keep the jobs that print page 5: ``` run(f"SELECT id FROM {TABLE} WHERE list_contains(generate_series(first_page, last_page), 5) ORDER BY id LIMIT 10") ``` ``` [(2,)] ``` ## 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 `generate_series()` is always computed by the Query Engine: - **In the `SELECT` list,** the scan reads the columns and the Query Engine builds the list for each row it returns. - **In `WHERE`,** the scan sends the columns for every row, and a `FILTER` step in the Query Engine builds the list 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 list_contains(generate_series(first_page, last_page), 5)") ``` ``` ┌───────────────────────────┐ │ PROJECTION │ │ ──────────────────── │ │ #2 │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ FILTER │ │ ──────────────────── │ │ list_contains │ │ (generate_series │ │(first_page, last_page), 5)│ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ │ │ Projections: │ │ first_page │ │ last_page │ │ id │ │ │ └───────────────────────────┘ ``` ## Make it faster - **Test a range with comparisons, not a list.** "Prints page 5" is `first_page <= 5 AND last_page >= 5`. Comparisons of a column with a constant are pushed down to VAST DataBase, so rows that don't match never leave storage, and the Query Engine doesn't build a list per row: ``` run(f"SELECT id FROM {TABLE} WHERE first_page <= 5 AND last_page >= 5 ORDER BY id LIMIT 10") plan(f"SELECT id FROM {TABLE} WHERE first_page <= 5 AND last_page >= 5") ``` ``` [(2,)] ┌───────────────────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ Projections: id │ │ │ └───────────────────────────┘ ``` - **Keep lists short.** `generate_series` builds the whole list for every row: `len(generate_series(100000))` is `100001`. ## Limitations and errors - **Integers and timestamps only.** A `DECIMAL`, a boolean, a date on its own or a list fails with `No function matches the given name and argument types`, and the error lists the forms `generate_series` takes. Cast a decimal to an integer first: `generate_series(CAST(x AS BIGINT))`. - **Timestamps need an interval.** `generate_series(ts1, ts2)` fails; add the step, such as `INTERVAL 1 DAY`. - **No time-zone timestamps.** `generate_series` on `TIMESTAMPTZ` values fails with `Extension Autoloading Error: An error occurred while trying to automatically install the required extension 'icu':`. Use `TIMESTAMP` values. - **A zero step returns an empty list,** not an error. ``` run("SELECT generate_series(TIMESTAMPTZ '2026-10-09 12:34:56+00', TIMESTAMPTZ '2026-10-11 12:34:56+00', INTERVAL 1 DAY)") run("SELECT generate_series(TIMESTAMP '2026-10-09 12:34:56', TIMESTAMP '2026-10-11 12:34:56', INTERVAL 1 DAY)") ``` ``` InternalError: Extension Autoloading Error: An error occurred while trying to automatically install the required extension 'icu': [([datetime.datetime(2026, 10, 9, 12, 34, 56), datetime.datetime(2026, 10, 10, 12, 34, 56), datetime.datetime(2026, 10, 11, 12, 34, 56)],)] ``` ## Similar functions | Function | Includes `stop` | `(1, 4)` | `(4)` | `(4, 1, -1)` | | --- | --- | --- | --- | --- | | `generate_series` | yes | `[1, 2, 3, 4]` | `[0, 1, 2, 3, 4]` | `[4, 3, 2, 1]` | | [range](/develop/docs/dev-database-reference-sql-functions-lists-range) | no | `[1, 2, 3]` | `[0, 1, 2, 3]` | `[4, 3, 2]` | | `SELECT * FROM generate_series(...)` ([table functions](/develop/docs/dev-database-reference-sql-functions-table-functions)) | yes | one row per value | | | ``` run("SELECT generate_series(1, 4), range(1, 4), generate_series(4), range(4), generate_series(4, 1, -1), range(4, 1, -1)") run("SELECT * FROM generate_series(1, 4)") ``` ``` [([1, 2, 3, 4], [1, 2, 3], [0, 1, 2, 3, 4], [0, 1, 2, 3], [4, 3, 2, 1], [4, 3, 2])] [(1,), (2,), (3,), (4,)] ``` Clean up: ``` run(f"DROP TABLE IF EXISTS {TABLE}") run(f"DROP SCHEMA IF EXISTS {SCHEMA}") conn.close() ``` ``` [] [] ``` ## See also - [List, struct and map functions](/develop/docs/dev-database-reference-sql-functions-lists-and-structs): all the list functions. - [range](/develop/docs/dev-database-reference-sql-functions-lists-range) and [table functions](/develop/docs/dev-database-reference-sql-functions-table-functions). - [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.