Merge Operator

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  • Published on Sep 26, 2025
  • 11 minute(s) read
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Overview

The Data Workflow Merge operator lets you combine or separate data from two data tables using key/value pairs. Controlling how data merges depends on the chosen feature and how you use the operator's two input ports.

The Merger operator supports the following features:

  • Intersection: Combines all table values that share the same key.

  • Inner: Combines all table values that share the same key, adding one table's values to the other table.

  • Outer: Separates out values from one table that do not share the same key as the other table.

You'll find the Merge operator under the Table group to the left of the Data Workflow canvas.

About the Info Window

Learn more about each setting in the Merge operator's Info window:

Info

Category

Grayed-out and non-adjustable setting indicating the operation type.

Label

Sets the label for your operator, displaying below the operator on your Data Workflow canvas.

This field is optional, but set a label if you use more than one of the same operator type. A label helps you identify your operators without opening any Info windows.

Keep Flag

This indicator displays in the DevTools Console for each row merged. Selecting True creates a flag that describes how you chose to merge the information. If True, a _merge_flag displays in the merged row.

Left refers to the data table connected to the upper input port. Right refers to the data table connected to the lower input port.

Merge Type

This drop-down lets you select how you want your data sets to merge.

  • Inner: Merges rows from the lower input table into the upper input table. The values merged must share the same key.

  • Outer: Separates all values from the upper input table whose key does not match the lower input table.

  • Intersection: Combines all values whose keys match.

You can use the Intersection option like a filter. You can filter a key to help you find matching values from both tables.

Merge Key

The reference key of the data you want to merge. This key can be the heading of a column in your data tables.

Renaming

This drop-down lets you rename, replace, or combine merged data.

  • Rename: Adds a suffix of _r to the merged data. If you perform an Inner merge, the upper input's values remain the same, but the lower input's values get the _r suffix.

  • Replace: Overwrites one of the table’s values with the other table's values. If you perform an Inner merge, the lower input's values replace the upper input's values.

  • Push: Combines values of both tables into an array. If you perform an Inner merge, the lower input's values combine with the upper input's values in an array. The resulting push is nameUpperValue,nameLowerValue.

Rows to Keep

This drop-down lets you pick which values you want to keep from your data tables. This setting is important when the values you want have more than one match.

  • First: Keeps the first row that matches in both tables.

  • Last: Keeps the last row that matches in both tables.

  • All: Keeps every row of both tables and combines them into a single array.

Merge Key

This is the reference key of the data you want to merge. This key can be the heading of a column in your data tables.

Adding a Merge Operator

For this example, create two Data Table components that store a list of annuitants and date of births in first table, and list of annuitants and their premiums in the second table. Then, set up a Data Workflow component to perform an intersection on the two data tables.

Configure the First Data Table Component

First, set up a Data Table component with a list of annuitants and their dates of birth.

  1. In the Module Builder, drag and drop a Data Table component onto your canvas.

  2. In the Property ID field, enter dtAnnuitant.

  3. In the data table, enter the following:

    A

    B

    1              

    annuitant

    dob

    2

    Kris Marrier

    01/01/1990

    3

    Mattie Poquette

    12/12/1989

    4

    Ezekiel Chui

    04/05/1980

  4. Click Save Component.

Configure the Second Data Table Component

Next, set up a Data Table component with another list of annuitants and their insurance policy premiums.

  1. Drag and drop a Data Table component onto your canvas, placing it below the dtAnnuitant Data Tablecomponent.

  2. In the Property ID field, enter dtPremiums.

  3. In the data table, enter the following:

    A

    B

    1                    

    annuitant

    premium

    2

    Kris Marrier

    50000

    3

    Mattie Poquette

    25000

    4

    Willow Kusko

    20000

       

  4. Click Save Component.

Configure the Data Workflow Component

Next, configure a Data Workflow component to merge the data table values based on a key. Then, add a Console operator to view the merged data in the DevTools Console.

  1. Drag and drop a Data Workflow component onto your canvas, placing it below your  your dtPremium Data Table component.

  2. In the Property ID and Canvas Label Text fields, enter dwfMergeIntersection.

Configure the First Input Operator

  1. Drag and drop an Input operator onto your Data Workflow canvas.

  2. Configure the  operator's Info window as follows:

    Info

    Category

    Input

    Component

    dtAnnuitant

    Required

    Yes

    Source

    Default

Configure the Second Input Operator

  1. Drag and drop another Input operator onto your Data Workflow canvas.

  2. Configure the  operator's Info window as follows:

    Info

    Category

    Input

    Component

    dtPremiums

    Required

    Yes

    Source

    Default

Configure the Merge Operator

  1. Drag and drop a Merge operator onto your Data Workflow canvas.

  2. Configure the  operator's Info window as follows:

    Info

    Category

    Merge

    label

    Merge Intersection

    Merge Type

    Intersection

    Keep Flag

    False

    Renaming

    Replace

    Rows to Keep

    First

    Merge Key

    Annuitant

  3. Connect the output port (right) of the dtAnnuitant Input operator to the upper input port (left) of the  Merge operator.

  4. Connect the output port (right) of the dtPremiums Input operator to the lower input port (left) of the Merge operator.

Configure the Console Operator

Add a Console operator as an output to the Merge operator so you can review the results in the DevTools Console.

  1. Drag and drop a Console operator onto your Data Workflow canvas.

  2. Configure the  operator's Info window as follows:

    Info

    Category

    Console

    Label

    Intersection Result

  3. Connect the output port (right) of the  Merge operator to the input port (left) of the Console operator.

  4. Click Save Component.

Here's how the completed Data Workflow looks:

Configure the Button Component

Lastly, configure a Button component to trigger the Data Workflow.

  1. Drag and drop a Button component onto your canvas, placing it below the Data Workflow component.

  2. In the Property ID, enter btnMergeIntersection.

  3. In the Label Text, enter Intersection Merge.

  4. From the Action Type drop-down, select Event.

  5. From the On Click drop-down, select dwfMergeIntersection.

  6. Click Save Component.

  7. Save your module.

Here's how the completed use case looks in the Module Builder:

Now you can test out your Data Workflow. Preview your module in Express View and open the DevTools Console. Then, click the button to see the results of the intersection function. The Data Workflow combines Kris Marrier and Mattie Poquette with their birthdates and insurance premiums, as expected. Ezekiel Chui and Willow Kusko do not share information between tables, so they do not merge or display in the new table.

Overview

The Data Workflow Merge operator lets you combine or separate data from two data tables using key/value pairs. Controlling how data merges depends on the chosen feature and how you use the operator's two input ports.

The Merger operator supports the following features:

  • Intersection: Combines all table values that share the same key.

  • Inner: Combines all table values that share the same key, adding one table's values to the other table.

  • Outer: Separates out values from one table that do not share the same key as the other table.

You'll find the Merge operator under the Table group to the left of your canvas.

About the Info Window

Learn more about each setting in the Merge operator's Info window:

Setting

Description

Category

Grayed-out and non-adjustable setting indicating the operation type.

Label

Sets the label for your operator, displaying below the operator on your Data Workflow canvas.

This field is optional, but set a label if you use more than one of the same operator type. A label helps you identify your operators without opening any Info windows.

Merge Type

This drop-down lets you select how you want your data sets to merge.

  • Inner: Merges rows from the lower input table into the upper input table. The values merged must share the same key.

  • Outer: Separates all values from the upper input table whose key does not match the lower input table.

  • Intersection: Combines all values whose keys match.

You can use the Intersection option like a filter. You can filter a key to help you find matching values from both tables.

Keep Flag

This indicator displays in the DevTools Console for each row merged. Selecting True creates a flag that describes how you chose to merge the information. If True, a _merge_flag displays in the merged row.

Left refers to the data table connected to the upper input port. Right refers to the data table connected to the lower input port.

Renaming

This drop-down lets you rename, replace, or combine merged data.

  • Rename: Adds a suffix of _r to the merged data. If you perform an Inner merge, the upper input's values remain the same, but the lower input's values get the _r suffix.

  • Replace: Overwrites one of the table’s values with the other table's values. If you perform an Inner merge, the lower input's values replace the upper input's values.

  • Push: Combines values of both tables into an array. If you perform an Inner merge, the lower input's values combine with the upper input's values in an array. The resulting push is nameUpperValue,nameLowerValue.

Rows to Keep

This drop-down lets you pick which values you want to keep from your data tables. This setting is important when the values you want have more than one match.

  • First: Keeps the first row that matches in both tables.

  • Last: Keeps the last row that matches in both tables.

  • All: Keeps every row of both tables and combines them into a single array.

Merge Key

This is the reference key of the data you want to merge. This key can be the heading of a column in your data tables.

Adding a Merge Operator

For this example, create two Data Table components that store a list of annuitants and date of births in first table, and list of annuitants and their premiums in the second table. Then, set up a Data Workflow component to perform an intersection on the two data tables.

Configure the First Data Table Component

First, set up a Data Table component with a list of annuitants and their dates of birth.

  1. In the Module Builder, drag and drop a Data Table component onto your canvas.

  2. In the Label Text and Property ID, enter dtAnnuitant.

  3. In the data table, enter the following:

    annuitant

    dob

    Kris Marrier

    01/01/1990

    Mattie Poquette

    12/12/1989

    Ezekiel Chui

    04/05/1980

  4. Click Save.

Configure the Second Data Table Component

Next, set up a Data Table component with another list of annuitants and their insurance policy premiums.

  1. Drag and drop another Data Table component onto your canvas.

  2. In the Label Text and Property ID, enter dtPremiums.

  3. In the data table, enter the following:

    annuitant

    premium

    Kris Marrier

    50000

    Mattie Poquette

    25000

    Willow Kusko

    20000

       

  4. Click Save.

Configure the Data Workflow Component

Next, configure a Data Workflow component to merge the data table values based on a key. Then, add a Console operator to view the merged data in the DevTools Console.

  1. Drag and drop a Data Workflow onto your canvas, placing it below your Data Table component.

  2. In the Canvas Label Text and Property ID fields, enter dwfMergeIntersection.

Configure the First Input Operator

  1. Drag and drop an Input operator onto your Data Workflow canvas.

  2. Configure the  operator's Info window as follows:

    Setting

    Value

    Category

    Input

    Component

    dtAnnuitant

    Required

    Yes

    Source

    Default

Configure the Second Input Operator

  1. Drag and drop another Input operator onto your Data Workflow canvas.

  2. Configure the  operator's Info window as follows:

    Setting

    Value

    Category

    Input

    Component

    dtPremiums

    Required

    Yes

    Source

    Default

Configure the Merge Operator

  1. Drag and drop a Merge operator onto your Data Workflow canvas.

  2. Configure the  operator's Info window as follows:

    Setting

    Value

    Category

    Merge

    Label

    Merge Intersection

    Merge Type

    Intersection

    Keep Flag

    False

    Renaming

    Replace

    Rows to Keep

    First

    Merge Key

    annuitant

  3. Connect the output port (right) of the dtAnnuitant Input operator to the upper input port (left) of the Merge operator.

  4. Connect the output port (right) of the dtPremiums Inputoperator to the lower input port (left) of the Merge operator.

Configure the Console Operator

Add a Console operator as an output to the Merge operator. This lets you see the result of the merge.

  1. Drag and drop a Console operator onto your Data Workflow canvas.

  2. Configure the  operator's Info window as follows:

    Setting

    Value

    Category

    Console

    Label

    Intersection Result

  3. Connect the output port (right) of the  Merge operator to the input port (left) of the Console operator.

  4. Click Save.

Here's how the completed Data Workflow looks:

Configure the Button Component

Lastly, configure a Button component to trigger the Data Workflow.

  1. Drag and drop a Button component onto your canvas, placing it below the Data Workflow component.

  2. In the Property ID, enter btnMergeIntersection.

  3. In the Label Text, enter Intersection Merge.

  4. From the Action Type drop-down, select Event.

  5. From the On Click drop-down, select dwfMergeIntersection.

  6. Click Save.

  7. Save your module.

Here's how the completed use case looks in the Module Builder:

Now you can test out your Data Workflow. Preview your module in Express View and open the DevTools Console. Then, click the button to see the results of the intersection function. The Data Workflow combines Kris Marrier and Mattie Poquette with their birthdates and insurance premiums, as expected. Ezekiel Chui and Willow Kusko do not share information between tables, so they do not merge or display in the new table.

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