Concatenate

Concatenate is a script load prefix that enables a dataset to be appended to an already existing in-memory table. It is often used to append different sets of transactional data to a single central fact table, or to build up common reference datasets of a specific type that originate from multiple sources. It is similar in functionality to a SQL UNION operator.

The resulting table from a concatenate operation will contain the original dataset with the new rows of data appended to the bottom of that table. The source and target tables may have different fields present. Where fields are different, the resulting table will be widened to represent the combined result of all fields present in both the source table and the target table.

Syntax:

Concatenate[ (tablename ) ] ( loadstatement | selectstatement )

Arguments
Argument	Description
tablename	The name of an existing table. The named table will be the target of the Concatenate operation and any records of data loaded will be appended to that table. If the tablename parameter isn't used, the target table will be the last loaded table before this statement.
loadstatement/selectstatement	The loadstatement/selectstatement argument that follows the tablename argument will be concatenated to the specified table.

Regional settings

Unless otherwise specified, the examples in this topic use the following date format: MM/DD/YYYY. The date format is specified in the SET DateFormat statement in your data load script. The default date formatting may be different in your system, due to your regional settings and other factors. You can change the formats in the examples below to suit your requirements. Or you can change the formats in your load script to match these examples.

Default regional settings in apps are based on the regional system settings of the computer or server where Qlik Sense is installed. If the Qlik Sense server you are accessing is set to Sweden, the Data load editor will use Swedish regional settings for dates, time, and currency. These regional format settings are not related to the language displayed in the Qlik Sense user interface. Qlik Sense will be displayed in the same language as the browser you are using.

Function example
Example	Result
Concatenate(Transactions) Load …. ;	The data loaded in the load statement below the Concatenate prefix will be appended to the existing in-memory table named Transactions (assuming that a table named Transactions has been loaded prior to this point in the load script.

Example 1 – Appending multiple sets of data to a target table with Concatenate load prefix

Overview

In this example you will load two scripts in sequential order.

The first load script contains an initial dataset with dates and amounts that is sent to a table named Transactions.
The second load script contains:
- A second dataset that is appended to the initial dataset by using the Concatenate prefix. This dataset has an additional field, type, that is not in the initial dataset.
- The Concatenate prefix.

Open the data load editor and add the load script below to a new tab.

First load script


Transactions: 
Load * Inline [ 

id, date, amount 
3750, 08/30/2018, 23.56 
3751, 09/07/2018, 556.31 
3752, 09/16/2018, 5.75 
3753, 09/22/2018, 125.00 
3754, 09/22/2018, 484.21 
3756, 09/22/2018, 59.18 
3757, 09/23/2018, 177.42 
];

Results

Load the data and open a sheet. Create a new table and add these fields as dimensions:

id
date
amount

First load script results table
id	date	amount
3750	08/30/2018	23.56
3751	09/07/2018	556.31
3752	09/16/2018	5.75
3753	09/22/2018	125.00
3754	09/22/2018	484.21
3756	09/22/2018	59.18
3757	09/23/2018	177.42

The table shows the initial dataset.

Second load script

Open the data load editor and add the load script below .


Concatenate(Transactions) 
Load * Inline [ 
id, date, amount, type 
3758, 10/01/2018, 164.27, Internal 
3759, 10/03/2018, 384.00, External 
3760, 10/06/2018, 25.82, Internal 
3761, 10/09/2018, 312.00, Internal 
3762, 10/15/2018, 4.56, Internal 
3763, 10/16/2018, 90.24, Internal 
3764, 10/18/2018, 19.32, External 
];

Results

Load the data and go to the sheet. Create this field as a dimension.

type

Second load script results table
id	date	amount	type
3750	08/30/2018	23.56	-
3751	09/07/2018	556.31	-
3752	09/16/2018	5.75	-
3753	09/22/2018	125.00	-
3754	09/22/2018	484.21	-
3756	09/22/2018	59.18	-
3757	09/23/2018	177.42	-
3758	10/01/2018	164.27	Internal
3759	10/03/2018	384.00	External
3760	10/06/2018	25.82	Internal
3761	10/09/2018	312.00	Internal
3762	10/15/2018	4.56	Internal
3763	10/16/2018	90.24	Internal
3764	10/18/2018	19.32	External

Note the null values in the type field for the first seven records loaded where type had not been defined.

Example 2 – Appending multiple sets of data to a target table using implicit concatenation

Overview

A typical use case for implicitly appending data is when you load several files of identically structured data and want to append them all to a target table.

For example, by using wildcards in file names with syntax such as:

	 myTable: 
	  Load * from [myFile_*.qvd] (qvd);

or in loops using constructs such as:


	for each file in filelist('myFile_*.qvd') 

	myTable: 
	Load * from [$(file)] (qvd); 

	next file

Implicit concatenation will take place between any two tables that are loaded with identically named fields, even if they aren't defined after one another in the script. This can lead to data being unintentionally appended to tables. If you don't want a secondary table with identical fields to be appended in this way, use the NoConcatenate load prefix. Renaming the table with an alternate table name tag is not sufficient to prevent implicit concatenation to occur. For more information, see NoConcatenate.

In this example you will load two scripts in sequential order.

The first load script contains an initial dataset with four fields that is sent to a table named Transactions.
The second load script contains a dataset with the same fields as the first dataset.

Open the data load editor and add the load script below to a new tab.

First load script


Transactions: 
Load * Inline [ 
id, date, amount, type 
3758, 10/01/2018, 164.27, Internal 
3759, 10/03/2018, 384.00, External 
3760, 10/06/2018, 25.82, Internal 
3761, 10/09/2018, 312.00, Internal 
3762, 10/15/2018, 4.56, Internal 
3763, 10/16/2018, 90.24, Internal 
3764, 10/18/2018, 19.32, External 
];

Results

Load the data and open a sheet. Create a new table and add these fields as dimensions:

id
date
amount
type

First load script results table
id	date	type	amount
3758	10/01/2018	Internal	164.27
3759	10/03/2018	External	384.00
3760	10/06/2018	Internal	25.82
3761	10/09/2018	Internal	312.00
3762	10/15/2018	Internal	4.56
3763	10/16/2018	Internal	90.24
3764	10/18/2018	External	19.32

The table shows the initial dataset.

Second load script

Open the data load editor and add the load script below .


Load * Inline [ 
id, date, amount, type 
3765, 11/03/2018, 129.40, Internal 
3766, 11/05/2018, 638.50, External 
];

Results

Load the data and go to the sheet.

Second load script results table
id	date	type	amount
3758	10/01/2018	Internal	164.27
3759	10/03/2018	External	384.00
3760	10/06/2018	Internal	25.82
3761	10/09/2018	Internal	312.00
3762	10/15/2018	Internal	4.56
3763	10/16/2018	Internal	90.24
3764	10/18/2018	External	19.32
3765	11/03/2018	Internal	129.40
3766	11/05/2018	External	638.50

The second dataset was implicitly concatenated onto the initial dataset because they had identical fields.

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