I need to find columns with missing values and calculate the percentage of missing data for each. Let me start by querying the column metadata to get null counts across all tables. ```json { "action": "tool_call", "reasoning": "The analytics.column_overview metadata table contains null_count for every column. I'll query it to find all columns with missing values and calculate the percentage missing based on their table's row count.", "tool": "query_sql", "args": { "sql": "SELECT co.table_name, co.column_name, co.null_count, t.row_count, ROUND(100.0 * co.null_count / NULLIF(t.row_count, 0), 2) AS pct_missing FROM analytics.column_overview co JOIN analytics.table_overview t ON co.table_name = t.table_name WHERE co.null_count > 0 ORDER BY pct_missing DESC, co.null_count DESC LIMIT 50", "purpose": "Find all columns with missing values and calculate the percentage missing for each", "source": "raw" } } ```