PPHA-714: SQL script to export NHS Numbers of submitted responses from DB to CSV (#439)

# What is the change?

Added a new SQL script that will be run to extract NHS numbers of
participants that have completed the questionnaire.


# Why are we making this change?

To share the NHS Numbers with one partner to inform them of participants
that have completed the questionnaire

Author: stephhou

scripts/sql/export_valid_responses.sql

@@ -0,0 +1,8 @@
+-- SQL script to export a csv file containing NHS numbers of submitted responses to a folder on an AVD.
+-- A valid response is defined as a response where the user has submitted the questionnaire.
+-- Run script using the psql command line tool on AVD.
+-- Update PATH_TO_EXPORT_FILE before running to specify the location and name of the exported file. The file will be created if it does not exist, or overwritten if it does.
+
+\set ON_ERROR_STOP on
+\copy (SELECT DISTINCT qu.nhs_number FROM questions_user qu JOIN questions_responseset qrs ON qrs.user_id = qu.id WHERE qrs.submitted_at IS NOT NULL) TO 'PATH_TO_EXPORT_FILE' WITH (FORMAT csv, HEADER true);
+