SQL Selector Operator and the Export Operator Compared
The main differences between the SQL Selector operator and the Export operator are
seen in their performance and feature sets.
The Export operator allows multiple sessions and multiple instances to extract data
from the Teradata Database. When exporting a large number of rows, it is usually better
to use the Export operator.
The SQL Selector operator only allows one session and one instance to extract rows
from the Teradata Database. When exporting a small number of rows, the SQL Selector
operator usually performs better than the Export operator.
The SQL Selector operator support of a single session and a single instance is similar
to a BTEQ Export operation.
Advantages of the SQL Selector Operator
The SQL Selector operator has features not found in the Export operator such as field
mode processing:
The SQL Selector operator has a Report Mode, known as Field Mode in the BTEQ environment.
All data retrieved in this mode is converted to character strings.
The SQL Selector operator is the only operator that can retrieve data from Teradata
Database in Field Mode and send data to the DataConnector operator in order to have
it written to an external target in the VARTEXT (or TEXT) format. The Export operator
cannot be used to extract data from a Teradata Database table and write it to an external
target in VARTEXT (or TEXT) format.
The SQL Selector operator can extract JSON, XML, or LOB data from Teradata Database.
The SQL Selector operator does not require an active load job. Instead, standard SQL
protocol is used on the single session. If it is difficult to acquire DBS resources
for running concurrent tasks, the SQL Selector operator is a logical choice rather
than the Export operator.