Profile Missing Activity Values by Site

You are given a dataset with missing values; how do you proceed?

Write a SQL query that profiles missing values in NHS activity records by site. Include sites with no activity records and treat missing site names as Unnamed site.

Output

1. One row per NHS site.
2. Columns: site_code, site_name, total_records, missing counts for each activity field, missing_value_count, and missing_value_rate_pct.
3. Include sites with zero activity records, and order by site_code ascending.

Output details

• Return columns in this order: site_code, site_name, total_records, missing_activity_date, missing_completed_attendances, missing_cancellations, missing_postcode, missing_value_count, missing_value_rate_pct.
• Count only actual activity records in total_records and missing-field counts, excluding the placeholder row for sites with no activity.
• Calculate missing_value_count as the sum of the four activity-field missing counts.
• Calculate missing_value_rate_pct as missing values divided by total_records * 4, multiplied by 100.
• Round missing_value_rate_pct to two decimal places and return 0.00 when total_records is zero.
• Group rows by the combination of site_code and site_name, allowing multiple rows with the same site_code when names differ.