Explaining the Merge Transform
The Merge transform combines incoming data sets with the same schema structure to produce a single output data set with the same schema as the input data sets. For example, use the Merge transform to combine two sets of address data as shown in the following figure.
Input/Output
Requirements
The Merge transform performs a union of the sources. All sources must have the same schema, including:
Sources must have the same number of columns.
Columns must be in the same order.
Columns must have the same names.
Columns must have the same data types, with the same lengths where possible.
If the input data set contains hierarchical data, the names and data types must match at every level of the hierarchy.
The output data has the same schema as the source data. The output data set contains a row for every row in the source data sets. The transform does not strip out duplicate rows. If columns in the input set contain nested schemas, the nested data is passed without change.
Hint
If you want to merge tables that do not have the same schema, add the Query transform to one of the tables before the Merge transform to redefine the schema to match the other table.The Merge transform does not offer any options.
