---
title: "QQ - How do I create a join between a field that is continuous on one table and discrete on the other?"
slug: "qq-how-do-i-create-a-join-between-a-field-that-is-continuous-on-one-table-and-discrete-on-the-other"
updated: 2022-09-27T13:54:31Z
published: 2022-09-27T13:54:32Z
canonical: "docs.datajet.app/qq-how-do-i-create-a-join-between-a-field-that-is-continuous-on-one-table-and-discrete-on-the-other"
---

> ## 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.

# QQ - How do I create a join between a field that is continuous on one table and discrete on the other?

A: Use the flags option on function Concat to create a continuous keyfield

How do i create a join between the following tables?

![](https://cdn.document360.io/73b6469b-c1e4-47e9-aa65-986c8ebd17ca/Images/Documentation/image-1664279925298.png)

Table1: BikeTripData

- 70,000,000 rows
- KeyField: Journey_ID
  - Alphanumeric: S123E343
  - Continuous | String

Table2: Journeys

- 100,000 rows
- KeyField: Journey_ID
  - Alphanumeric: S123E343
  - Discrete | String | Short | 933

Issues:

- Can't create link directly because we get "Continuous join fields must be same data type and field type. Cannot add join"
- Using MakeContinuousKey on Journeys.Journey_ID doesn't work, as this creates an integer

Resolution:

- Journey_ID is created using the Concat function.     Use the flags option, and set to NOORD to create the field as a continuous field:

```json
{
  "method": "BuildBakedField",
  "targetTable": "Journeys",
  "overwrite": true,
  "name": "Journey_ID",
  "function": "string",
  "p1": "CONCAT(A,B,C,D,E,F)",
  "p2": "E_ID",
  "p3": "S_ID",
  "project": "JoinDiscreteContinuous",
  "flags": "NOORD"
}
```