Join

Introduction

Functions

Join function supports to integrate data in two forms into one form. Join function supports the following three ways currently:

Application Scenarios

When using Join function, you need to set common fields in left form and right form. These fields you have set are join fields, which you can use to integrate data left and right.

For instance, one form is students' math scores and the other form is Students' English scores. The common field is student name. You can integrate these two forms' data into one form to view students' subject scores.

Preview

The output forms using different join ways are shown in the following:

Setting Procedure

Data Source Forms

The data source forms in Join are Math Scores form and English Scores form.

Creating Data Streams

Go to App Management > Data Factory > New Data Stream.

Selecting Data Sources

Rename the data stream, add 2 Input nodes, and select Math Scores form and English Scores form as input sources.

Adding Join Node

Add one Join data processing node in design canvas of the data stream and connect the two input nodes with it respectively.

Setting Nodes

You need to set connection methods and connection fields in Join node.

1. Connection Methods

There are four ways to connect: Inner Join, Left Join, Right Join, and Full Join.

Data will be matched according to connection fields in Join. Common data with the same connection fields will be connected left and right according to connection methods. For instance, Inner Join takes the intersectional data of two forms. Only there both have connection fields in two forms, can the match go on.

a. How to distinguish left form and right form

Way 1: The form that is connected to Join node first is left form. The form that is connected to Join node later is right form.

Way 2: After connection, you can view left form and right form in Node Configuration.

2. Integrating Connection Fields

If you choose Merge Connection Field, the connection fields will be merged into one field.

The following pictures show the difference between whether merging connection fields or not:

Note: The orange fields in pictures above represent connection fields.

2. Connection Field

Connection Field is the condition to integrate two forms into one form. If there are multi connection conditions, you can add multi connection fields. Only data whose connection fields fully match can be connected. You can preview the effect after connection in Data Preview.

Renaming Nodes

In order to better mark calculation rules of every data processing step in the data stream, you can rename the nodes in the data stream.

Saving and Outputting

After Union, if you need further calculate data, you can add other data processing nodes. After finishing the operation, you need to connect them with Output node and click Save.

Demonstration

You can preview the data after Join in the dashboard.

Different connection methods lead to different connection effects.

You can also enable Sync output table data into forms to make a copy data.

Note

1. Null values cannot match each other

If there are null values in same connection fields of 2 forms when setting Join node, these null values cannot match each other.

2. Data Preview Limitation

You can at most preview 200 records of data in Data Preview. If you want to view complete data, you can further analyze and display in dashboards.

3. Nesting Use of Join

One Join node supports to integrate 2 forms currently. If you have demand on connecting many data forms, you can nest multi Join nodes.

You can connect A form with B form through Join, then connect C form with the Join node through another Join node, and so on.

4. Date Matching Accuracy

If connection field belongs to Date&Time type, then you can choose the match accuracy freely. The matching accuracy of Date&Time field is Days by default.