---
title: "sum"
slug: "dev-database-reference-sql-functions-aggregate-sum"
updated: 2026-10-30T18:18:46Z
published: 2026-10-30T18:18:46Z
canonical: "docs.vastdata.com/dev-database-reference-sql-functions-aggregate-sum"
---

> ## 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.

# sum

*Applies to VAST Cluster 5.5.*

*[Functions](/develop/docs/dev-database-reference-sql-functions-index) › [Aggregate and analytic functions](/develop/docs/dev-database-reference-sql-functions-aggregate) › Sums and averages.* Adds up the non-NULL values of a number column or expression. On a `BOOLEAN`, it counts the true values.

## Syntax

```
sum(x)
```

| Argument | Type | Description |
| --- | --- | --- |
| `x` | a number (any integer type, `FLOAT`, `DOUBLE`, `DECIMAL`) or a `BOOLEAN` | The values to add up. NULLs are skipped. |

**Returns:** depends on the type of `x`:

| `x` | Result | In Python (ADBC) |
| --- | --- | --- |
| `TINYINT` to `BIGINT`, `UTINYINT` to `UBIGINT`, `HUGEINT` | `HUGEINT`, a 128-bit integer | `Decimal` |
| `BOOLEAN` | `HUGEINT`: the number of true values | `Decimal` |
| `FLOAT`, `DOUBLE` | `DOUBLE` | `float` |
| `DECIMAL(p, s)` | `DECIMAL(38, s)` | `Decimal` |

## 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_aggregate_sum`. 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 order lines: a quantity, a unit price, a weight in kilograms, whether the line is paid, and the IDs of the items shipped. 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_aggregate_sum"'

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, "<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}.order_lines"
run(f"CREATE SCHEMA IF NOT EXISTS {SCHEMA}")
run(f"CREATE TABLE IF NOT EXISTS {TABLE} "
    "(id BIGINT, qty INTEGER, price DECIMAL(10,2), weight DOUBLE, paid BOOLEAN, items BIGINT[])")
run(f"INSERT INTO {TABLE} VALUES "
    "(1, 2, 9.99, 1.5, true, [101, 102]), "
    "(2, 1, 24.50, 0.25, false, [103]), "
    "(3, 5, 3.10, 2.0, true, []), "
    "(4, NULL, NULL, NULL, NULL, NULL)")
```

```
[]
[]
[(4,)]
```

## What it does

`sum(x)` is an aggregate: it adds up the values of `x` over the rows of the query, skips the NULLs, and returns one value. `x` can be a column or an expression, such as `qty * price` or `CASE WHEN ... THEN 1 ELSE 0 END`.

The result type is wide enough that integer sums don't overflow in practice: a sum of `BIGINT` values is a 128-bit `HUGEINT`, so two rows at the largest `BIGINT`, 9223372036854775807, add up to 18446744073709551614 without an error. A `DECIMAL(p, s)` sum keeps the scale `s` and widens to 38 digits, and is exact: ten rows of `0.10` add up to `1.00`. A `DOUBLE` sum is a floating-point sum: it can round, and it doesn't fail on overflow (see [NULLs and edge cases](/develop/docs/dev-database-reference-sql-functions-aggregate-sum#nulls-and-edge-cases)).

On a `BOOLEAN`, true counts as 1 and false as 0, so `sum(paid)` is the number of paid lines.

## NULLs and edge cases

| Input | Result |
| --- | --- |
| NULL values | Skipped |
| Only NULLs, or `sum(NULL)` | NULL |
| No rows (an empty table, or a `WHERE` that matches nothing) | NULL; use `coalesce(sum(x), 0)` for 0 |
| `sum(42)` with no `FROM` | `42` |
| A constant over a table: `sum(9223372036854775807)` | The constant times the number of rows, as a `HUGEINT` |
| A `DOUBLE` sum too large | `inf`, not an error |
| `NaN` among the values, or `inf` and `-inf` | `nan` |
| A `DECIMAL(38, s)` sum too large | Error: `Overflow in HUGEINT addition: ...` |
| An integer expression that overflows before the sum: `sum(id * 9223372036854775807)` | Error: `Overflow in multiplication of INT64 (...)!` |
| A string, date, time, timestamp, interval or list | Error: `No function matches the given name and argument types`, for example `&apos;sum(VARCHAR)&apos;` |
| `sum(DISTINCT x)` | Error: `The operator &apos;UNGROUPED_AGGREGATE&apos; type=8 is currently not supported for this usage.` |

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-aggregate-sum#set-up-the-examples):

```
run(f"SELECT sum(qty), sum(price), sum(weight), sum(paid) FROM {TABLE}")
run(f"SELECT sum(qty) FROM {TABLE} WHERE id = 4")
run(f"SELECT sum(qty), coalesce(sum(qty), 0) FROM {TABLE} WHERE id > 100")
run("SELECT sum(NULL), sum(42)")
run(f"SELECT sum(9223372036854775807) FROM {TABLE}")
run("SELECT sum(x) FROM (SELECT 0.1::DOUBLE AS x FROM range(10))")
run("SELECT sum(x) FROM (SELECT 0.1::DECIMAL(10,2) AS x FROM range(10))")
run("SELECT sum(x) FROM (VALUES (1.0e308::DOUBLE), (1.0e308::DOUBLE)) v(x)")
run("SELECT sum(x) FROM (VALUES ('inf'::DOUBLE), ('-inf'::DOUBLE)) v(x)")
run("SELECT sum(x) FROM (VALUES (99999999999999999999999999999999999999::DECIMAL(38,0)), "
    "(99999999999999999999999999999999999999::DECIMAL(38,0))) v(x)")
run(f"SELECT sum(id * 9223372036854775807) FROM {TABLE}")
run(f"SELECT sum('10') FROM {TABLE}")
run(f"SELECT sum(DISTINCT qty) FROM {TABLE}")
```

```
[(Decimal('8'), Decimal('37.59'), 3.75, Decimal('2'))]
[(None,)]
[(None, Decimal('0'))]
[(None, Decimal('42'))]
[(Decimal('36893488147419103228'),)]
[(1.0,)]
[(Decimal('1.00'),)]
[(inf,)]
[(nan,)]
OSError: Overflow in HUGEINT addition: 99999999999999999999999999999999999999 + 99999999999999999999999999999999999999
OSError: Overflow in multiplication of INT64 (2 * 9223372036854775807)!
InternalError: Binder Error: No function matches the given name and argument types 'sum(VARCHAR)'. You might need to add explicit type casts.
InternalError: The operator 'UNGROUPED_AGGREGATE' type=8 is currently not supported for this usage.
```

## Examples

The total quantity, the total of the unit prices, the total weight and the number of paid lines:

```
run(f"SELECT sum(qty), sum(price), sum(weight), sum(paid) FROM {TABLE}")
```

```
[(Decimal('8'), Decimal('37.59'), 3.75, Decimal('2'))]
```

The value of all the lines, and of the paid ones only, from an expression. `qty * price` is an `INTEGER` times a `DECIMAL(10,2)`, so the sum is a `DECIMAL` and exact:

```
run(f"SELECT sum(qty * price), sum(qty * price) FILTER (WHERE paid) FROM {TABLE}")
```

```
[(Decimal('59.98'), Decimal('35.48'))]
```

The number of items shipped over all the lines, and the total of their IDs. `sum()` doesn't take a list: [unnest](/develop/docs/dev-database-reference-sql-functions-table-functions-unnest) the lists into rows first, or use [list_sum](/develop/docs/dev-database-reference-sql-functions-lists-list-sum) to add up the elements of each list. `list_sum` of an empty list is NULL:

```
run(f"SELECT count(*), sum(x) FROM (SELECT unnest(items) AS x FROM {TABLE})")
run(f"SELECT id, list_sum(items) FROM {TABLE} ORDER BY id LIMIT 10")
```

```
[(3, Decimal('306'))]
[(1, Decimal('203')), (2, Decimal('103')), (3, None), (4, None)]
```

## How it runs in VAST

The Query Engine runs on the cluster's CNodes. A `sum` query has two steps, which [EXPLAIN](/develop/docs/dev-database-reference-sql-explain) shows:

1. **A scan in VAST DataBase** (`VAST_SCAN`). It reads only the columns the sum uses, and evaluates the `WHERE` conditions it can [push down](/develop/docs/dev-database-reference-pushdowns), so rows that don't match never leave storage.
2. **One aggregate step** (`UNGROUPED_AGGREGATE`) in the Query Engine. It computes the expression inside `sum()` for each row the scan sends, adds it up, and returns one row.

The plan of a sum with a pushed-down `WHERE` condition. The condition doesn't appear in the plan, because the scan evaluates it:

```
plan(f"SELECT sum(weight) FROM {TABLE} WHERE id > 1")
```

```
┌───────────────────────────┐
│    UNGROUPED_AGGREGATE    │
│    ────────────────────   │
│        Aggregates:        │
│        sum(weight)        │
└─────────────┬─────────────┘
┌─────────────┴─────────────┐
│         VAST_SCAN         │
│    ────────────────────   │
│    Function: VAST_SCAN    │
│    Projections: weight    │
│                           │
└───────────────────────────┘
```

## Make it faster

- **Filter in `WHERE`, not in `FILTER (WHERE ...)`.** `sum(x) FILTER (WHERE id &gt; 1)` and `sum(x) ... WHERE id &gt; 1` give the same result, but the `FILTER` condition is evaluated in the aggregate step, after the scan has sent every row, and the `WHERE` condition in VAST DataBase. Use `FILTER` when you need different conditions for different sums in one query:

```
plan(f"SELECT sum(weight) FILTER (WHERE id > 1) FROM {TABLE}")
```

```
┌───────────────────────────┐
│    UNGROUPED_AGGREGATE    │
│    ────────────────────   │
│        Aggregates:        │
│ sum(weight) FILTER (WHERE │
│ (id > 1)) Filter: (id > 1)│
└─────────────┬─────────────┘
┌─────────────┴─────────────┐
│         VAST_SCAN         │
│    ────────────────────   │
│    Function: VAST_SCAN    │
│                           │
│        Projections:       │
│             id            │
│           weight          │
│                           │
└───────────────────────────┘
```

- **Keep functions out of the `WHERE` condition.** `WHERE abs(weight) &gt; 1` isn't pushed down: the plan shows a `FILTER` step in the Query Engine above the scan. Compare the raw column with a constant when you can.
- **Compute several sums in one query.** They share one scan and one aggregate step.
- **Sort the table on the column you filter by.** Sorting lets the scan skip whole blocks of rows; see [indexing and data skipping](/develop/docs/dev-database-guides-indexing-and-data-skipping).

## Limitations and errors

- **Numbers and `BOOLEAN` only.** A string, a date, a time, a timestamp, an interval or a list fails with `No function matches the given name and argument types`; the error lists the types `sum` takes. A number stored as text needs a cast: `sum(CAST(s AS BIGINT))`.
- **Overflow inside the expression.** `sum()` itself doesn't overflow on integers, but the expression inside it is computed in the column's type first: `id * 9223372036854775807` overflows `BIGINT` before the sum sees it. Cast to `DOUBLE` first if an approximate result is enough: `sum(id::DOUBLE * 9223372036854775807)`.
- **`DECIMAL(38, s)` sums can overflow.** A sum beyond 38 digits fails with `Overflow in HUGEINT addition`.
- **`DOUBLE` sums round.** Use a `DECIMAL` column for money and other values that must add up exactly. `fsum`, `kahan_sum` and `sumkahan` aren't available ([not available](/develop/docs/dev-database-reference-sql-functions-aggregate)).
- **No `GROUP BY` or `DISTINCT`.** A sum per group fails with `The operator &apos;HASH_GROUP_BY&apos; type=9 is currently not supported.`; `sum(DISTINCT x)` fails with `The operator &apos;UNGROUPED_AGGREGATE&apos; type=8 is currently not supported for this usage.`
- **Window forms.** `sum(x) OVER (ROWS UNBOUNDED PRECEDING)` runs, as a running total in the order the scan returns the rows. `OVER ()`, `OVER (ORDER BY ...)` and `OVER (PARTITION BY ...)` fail with `The operator &apos;WINDOW&apos; type=6 is currently not supported.` See [window functions](/develop/docs/dev-database-reference-sql-functions-aggregate-window-functions).

```
run(f"SELECT sum(id::DOUBLE * 9223372036854775807) FROM {TABLE}")
run(f"SELECT sum(items) FROM {TABLE}")
run(f"SELECT paid, sum(qty) FROM {TABLE} GROUP BY paid")
run(f"SELECT id, sum(qty) OVER (ORDER BY id) FROM {TABLE}")
```

```
[(9.223372036854776e+19,)]
InternalError: Binder Error: No function matches the given name and argument types 'sum(BIGINT[])'. You might need to add explicit type casts.
InternalError: The operator 'HASH_GROUP_BY' type=9 is currently not supported.
InternalError: The operator 'WINDOW' type=6 is currently not supported.
```

## Similar functions

| Function | Returns |
| --- | --- |
| `sum(x)` | the total of the non-NULL values |
| [avg](/develop/docs/dev-database-reference-sql-functions-aggregate-avg) `(x)` | the total divided by the number of non-NULL values, as a `DOUBLE` |
| [product](/develop/docs/dev-database-reference-sql-functions-aggregate-product) `(x)` | the values multiplied together, as a `DOUBLE` |
| [count_if](/develop/docs/dev-database-reference-sql-functions-aggregate-count-if) `(condition)` | the number of rows where the condition is true; the same as `sum(CASE WHEN condition THEN 1 ELSE 0 END)` |
| [list_sum](/develop/docs/dev-database-reference-sql-functions-lists-list-sum) `(list)` | the total of the elements of one list, per row |

```
run(f"SELECT sum(qty), avg(qty), product(qty), sum(CASE WHEN paid THEN 1 ELSE 0 END), count_if(paid) FROM {TABLE}")
run("SELECT list_sum([1, 2, 3])")
```

```
[(Decimal('8'), 2.6666666666666665, 10.0, Decimal('2'), Decimal('2'))]
[(Decimal('6'),)]
```

Clean up:

```
run(f"DROP TABLE IF EXISTS {TABLE}")
run(f"DROP SCHEMA IF EXISTS {SCHEMA}")
conn.close()
```

```
[]
[]
```

## See also

- [Aggregate and analytic functions](/develop/docs/dev-database-reference-sql-functions-aggregate): all the aggregates, and the ones that aren't available.
- [avg](/develop/docs/dev-database-reference-sql-functions-aggregate-avg), [count_if](/develop/docs/dev-database-reference-sql-functions-aggregate-count-if) and [FILTER](/develop/docs/dev-database-reference-sql-functions-aggregate-filter-clause).
- [Pushdowns](/develop/docs/dev-database-reference-pushdowns) and [EXPLAIN](/develop/docs/dev-database-reference-sql-explain).