---
title: "HOURSBEFOREMAX(A)"
slug: "datetimetransform-template-1"
updated: 2021-11-11T14:30:46Z
published: 2021-11-11T14:30:46Z
canonical: "docs.datajet.app/datetimetransform-template-1"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.datajet.app/llms.txt
> Use this file to discover all available pages before exploring further.

# HOURSBEFOREMAX(A)

## DateTime Transform: HOURSBEFOREMAX(A)

## Returns the number of hours before the maximum value of DateTime A

`HOURSBEFOREMAX(A) =  HoursDiff(Max(A),A)`

where

- Max(A) = Maximum value in Field A

- A = Value of current record

- HoursDiff(Max(A),A) = total number of hours between Max(A) and A

## Purpose

Use this function to:

- Calculate hourly difference between an individual transaction and the most recent transaction
- Calculate the age, in hours, of an event

## Return Value

| Property | Value |
| --- | --- |
| **FieldType** | Integer |
| **FieldSize** | Med / High |
| **DataType** | Discrete / Continuous |
| **DataSize** | Integer |

```shell
Example Return Value: -N....N  where N = maximum difference in hours between records in Field A
```

![](https://cdn.document360.io/73b6469b-c1e4-47e9-aa65-986c8ebd17ca/Images/Documentation/DT_HOURSBEFOREMAX_Sample.PNG)

## Parameters

| Parameter | JSON | Description |
| --- | --- | --- |
| **Table** | “targetTable”: “MyTableName” | The target table on which the new field will be created |
| **Filter** | “dataset”: {DataSet_JSON} | Optional. If a filter is applied, records not in the filter Recordset will be returned as null. |
| **DateTime Function** | “p1”: “HOURSBEFOREMAX(A)” | HOURSBEFOREMAX(A) |
| **A** | “p2”: “DateTimeFieldName” “p2”: “#YYYY-MM-DD HH:MM:SS” | Required. The DateTime field from which to extract the Max Hour and the Hour to compare it with. Must be on the target table. *Supports:* - **DataType:** Discrete / Continuous - **Field Type:** DateTime - **Fixed Value:** #YYYY-MM-DD HH:MM:SS, e.g. #2021-04-05 11:01:08 |

## JSON Sample

![](https://cdn.document360.io/73b6469b-c1e4-47e9-aa65-986c8ebd17ca/Images/Documentation/DT_HOURSBEFOREMAX_JSON.PNG)

## Usage Notes

See also:

- HOURSDIFF(A,B)   (DateTime)
- Engineering | Expression Field

## Example

| Example | Details |
| --- | --- |
| **Description** | Calculate number of hours between current row and maximum DateTime for the field |
| **Input** | - Table: = [transactions] - Function: = DateTimeTransform - **DateTimeFunction: =HOURSBEFOREMAX(A)** - A:= [transactions].[DateTime] - Name: =HoursBeforeMax |
| **Sample** | ![](https://cdn.document360.io/73b6469b-c1e4-47e9-aa65-986c8ebd17ca/Images/Documentation/DT_HOURSBEFOREMAX_Example.PNG) |