The following figure shows the SQL transformation ports:

All of the ports are pass-through ports except the SQLError and Sequence_No output ports.

When you create the SQL transformation, the Developer tool creates the SQLError port. The SQLError port returns SQL errors from the database. You cannot delete this port.

The Sequence_No output port returns the sequence number value from the Sequence_Number table.

When you configure a query SELECT clause, the number and the order of the output ports must match the number and order of the fields in the SELECT clause. The native type for the port must match the datatype of the column in the database.

When the number of output ports is more than the number of columns in the SELECT clause, the extra ports receive a NULL value. When the number of output ports is less than the number of columns in the SELECT clause, the Data Integration Service generates a row error.

To create a pass-through port, drag the ports from the Union transformation to the SQL transformation. In the Ports view, select Copy to Output. The Developer tool creates the output ports and adds the suffix "_output" to each port name.