Data Import
Union by Position
By default, DuckDB unifies the columns of these different files **by position**. This means that the first column in each file is combined together, as well as the second column in each file, etc. For example, consider the following two files.  
[`flights1.csv`](https://duckdb.org/data/flights1.csv):  
```csv
FlightDate|UniqueCarrier|OriginCityName|DestCityName
1988-01-01|AA|New York, NY|Los Angeles, CA
1988-01-02|AA|New York, NY|Los Angeles, CA
```  
[`flights2.csv`](https://duckdb.org/data/flights2.csv):  
```csv
FlightDate|UniqueCarrier|OriginCityName|DestCityName
1988-01-03|AA|New York, NY|Los Angeles, CA
```  
Reading the two files at the same time will produce the following result set:  
<div class="narrow_table"></div>  
| FlightDate | UniqueCarrier | OriginCityName |  DestCityName   |
|------------|---------------|----------------|-----------------|
| 1988-01-01 | AA            | New York, NY   | Los Angeles, CA |
| 1988-01-02 | AA            | New York, NY   | Los Angeles, CA |
| 1988-01-03 | AA            | New York, NY   | Los Angeles, CA |  
This is equivalent to the SQL construct [`UNION ALL`](#docs:sql:query_syntax:setops::union-all).