<invoke name="query_sql"> <parameter name="purpose">Per-column missing (NULL or blank) count and percentage across all data columns</parameter> <parameter name="source">raw</parameter> <parameter name="sql">WITH t AS (SELECT to_json(r) AS j FROM raw.AI_Usage_and_Impact_on_Students_and_Professionals r), kv AS (SELECT u.k AS column_name, json_extract_string(t.j, '$.' || u.k) AS v FROM t, UNNEST(['User_ID','Age','Gender','Country','User_Type','Education_Level','Profession','Monthly_Income','AI_Tool','AI_Purpose','AI_Usage_Hours_Per_Day','Tasks_Performed','Monthly_AI_Cost','Productivity_Score','Accuracy_Rating','Satisfaction_Score','Time_Saved_Hours_Per_Week','Work_or_Study_Hours_Per_Day','Would_Recommend']) AS u(k)) SELECT column_name, COUNT(*) FILTER (WHERE v IS NULL OR TRIM(v) = '') AS missing_count, ROUND(100.0 * COUNT(*) FILTER (WHERE v IS NULL OR TRIM(v) = '') / COUNT(*), 2) AS pct_missing FROM kv GROUP BY column_name ORDER BY missing_count DESC, column_name</parameter> </invoke>