---
title: Sum
---

`SUM` computes the total over a specific column:

```sql
SELECT SUM(rating) FROM mock_items
WHERE id @@@ paradedb.all();
```

<Note>
  The field being summed, in this case `rating`, must be indexed as
  [fast](/documentation/indexing/fast_fields).
</Note>

By default, `SUM` ignores null values. Use `COALESCE` to include them in the final sum:

```sql
SELECT SUM(COALESCE(rating, 0)) FROM mock_items
WHERE id @@@ paradedb.all();
```

To verify that `SUM` was pushed down, look for a `ParadeDB Aggregate Scan` with `sum` in the `EXPLAIN` output:

```sql
EXPLAIN SELECT SUM(rating) FROM mock_items
WHERE id @@@ paradedb.all();
```

```sql Expected Response
                                               QUERY PLAN
--------------------------------------------------------------------------------------------------------
 Custom Scan (ParadeDB Aggregate Scan) on mock_items  (cost=0.00..0.00 rows=0 width=8)
   Index: search_idx
   Tantivy Query: {"with_index":{"query":"all"}}
   Aggregate Definition: {"0":{"sum":{"field":"rating"}},"_doc_count":{"value_count":{"field":"ctid"}}}
(4 rows)
```
