I need to identify columns with missing values and calculate the percentage of missing data for each. Let me start by querying the column metadata to find columns with null counts. ```json { "action": "tool_call", "reasoning": "The analytics.column_overview metadata table contains null_count for every column across all tables. I'll query it to find columns with missing values and calculate the percentage missing based on the row counts from analytics.table_overview.", "tool": "query_sql", "args": { "sql": "WITH table_rows AS (SELECT table_name, row_count FROM analytics.table_overview), column_nulls AS (SELECT co.table_name, co.column_name, co.null_count, tr.row_count FROM analytics.column_overview co JOIN table_rows tr ON co.table_name = tr.table_name WHERE co.null_count > 0) SELECT table_name, column_name, null_count, row_count, ROUND(100.0 * null_count / row_count, 2) AS pct_missing FROM column_nulls ORDER BY pct_missing DESC, null_count DESC", "purpose": "Find all columns with missing values and calculate the percentage missing for each", "source": "raw" } } ```