> For the complete documentation index, see [llms.txt](https://docs.docbits.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.docbits.com/administration-and-setup/settings/global-settings/document-types/script/scripting-in-docbits/sample-scripts/table-sum-validation.md).

# Table Sum Validation

## What does this script do?

Validates that the sum of all line totals in the invoice table matches the document's net amount. If there is a discrepancy greater than 0.01, the calculated sum replaces the extracted net amount — ensuring consistency between line items and header fields.

## Trigger

`AFTER_FORMATTING` on document type **INVOICE**

## Full Script

```python
table = tables_dict.get("INVOICE_TABLE")
if table:
    # Calculate sum of all line totals
    total = 0
    for row in table["rows"]:
        line_total = get_column_value(row, "LINE_TOTAL", "0")
        try:
            total += float(line_total)
        except ValueError:
            pass

    # Compare with extracted net amount
    net_amount = get_field_value(document_data, "net_amount", "0")
    try:
        if abs(float(net_amount) - total) > 0.01:
            # Line sum differs from header — update net amount
            set_amount_value(document_data, "net_amount", str(round(total, 2)))
    except ValueError:
        pass
```

## Variation: Mark as invalid instead of overwriting

```python
table = tables_dict.get("INVOICE_TABLE")
if table:
    total = 0
    for row in table["rows"]:
        line_total = get_column_value(row, "LINE_TOTAL", "0")
        try:
            total += float(line_total)
        except ValueError:
            pass

    net_amount = get_field_value(document_data, "net_amount", "0")
    try:
        diff = abs(float(net_amount) - total)
        if diff > 0.01:
            set_field_as_invalid(document_data, "net_amount",
                f"Line total sum ({round(total, 2)}) differs from net amount ({net_amount})")
        else:
            set_field_as_valid(document_data, "net_amount", "Amounts match")
    except ValueError:
        pass
```

## Step-by-Step Explanation

1. **Get invoice table** from `tables_dict`
2. **Sum all LINE\_TOTAL values** across table rows
3. **Compare** calculated sum with the extracted net amount
4. **Update or flag** — either replace the net amount or mark it as invalid

## Functions Used

* [get\_column\_value()](/administration-and-setup/settings/global-settings/document-types/script/scripting-in-docbits/table-functions.md#get_column_value) — Read column values from rows
* [get\_field\_value()](/administration-and-setup/settings/global-settings/document-types/script/scripting-in-docbits/field-functions.md#get_field_value) — Read net amount
* [set\_amount\_value()](/administration-and-setup/settings/global-settings/document-types/script/scripting-in-docbits/field-functions.md#set_amount_value) — Set corrected amount
* [set\_field\_as\_invalid()](/administration-and-setup/settings/global-settings/document-types/script/scripting-in-docbits/field-functions.md#set_field_as_invalid) — Mark field as invalid
* [set\_field\_as\_valid()](/administration-and-setup/settings/global-settings/document-types/script/scripting-in-docbits/field-functions.md#set_field_as_valid) — Mark field as valid


---

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