Concatenate or Forced Concatenation:

When we use Concatenate keyword to add up two tables which have common columns to avoid synthetic key creation.

Rules:

The names of the fields must be exactly the same.

Unless a table name of a previously loaded table is specified in the concatenate statement the concatenate prefix uses the last previously created table.

NoConcatenate:

When we use NoConcatenate keyword, synthetic key gets created if there more than one same column.

Auto Concatenate:

If the field names and the number of fields of two or more loaded tables are exactly the same, QlikView will automatically concatenate the content of the different statements into one table.

Example:

load a, b, c from table1.csv;

load a, c, b from table2.csv;

The resulting internal table has the fields a, b and c. The number of records is the sum of the numbers of records in table 1 and table 2.

Rules:

The number and names of the fields must be exactly the same.