In QlikView, if the number of fields and field names of two or more tables are same then the tables are Concatenated into one table.

It usually happens when you are loading tables from different datasources and don’t realize that field names and field numbers in different tables are same. After the dataload you expect to see two separate tables in table viewer but instead see only one.

Concatenate happens in different ways.

1. Automatic Concatenation

2. Forced Concatenation

3. No Concatenation

In this Part 1 i will cover Automatic Concatenation

 Automatic Concatenation

As stated above,when field names and field numbers of 2 or more tables is same then the tables are concatenated into one table. Order of the columns in tables does not matter. Also The Sum of records in the resulting table is the Sum of the number of records in Table 1 and Table 2.

Let us load first table and see it in the table viewer

          

As you can see that this table has following 4 rows.

Let us now load 2 tables, with same name and number of columns.

Table Cust_1 has 4 rows and table Cust_2 has 3 rows. Order of columns are different.

Observe Table viewer and number of rows in the resulting table.

                                           

As you can see the number of rows in the resulting table is 7 rows. The Sum of records in the resulting table is the Sum of the number of records in Table 1 and Table 2.

For details on Forced Concatenation and Preventing Concatenation, please visit Concatenate and NoConcatenate in QlikView – Part 2.