refactor: add partition calculation strategy and implement estimation logic; enhance table analyzers for max/min column queries

internal/app/etl/table_analyzers/mssql.go

@@ -196,6 +196,29 @@ GROUP BY t.name`
 	return rowsCount, nil
 }
 
+func (ta *MssqlTableAnalyzer) QueryMaxMinFromColumn(
+	ctx context.Context,
+	tableInfo config.TableInfo,
+	columnName string,
+) (etl.MaxMinColumnResult, error) {
+	query := fmt.Sprintf(`
+SELECT
+	MIN([%s]) AS min_value,
+	MAX([%s]) AS max_value
+FROM [%s].[%s]`, columnName, columnName, tableInfo.Schema, tableInfo.Table)
+
+	ctxTimeout, cancel := context.WithTimeout(ctx, 1*time.Minute)
+	defer cancel()
+
+	result := etl.MaxMinColumnResult{}
+	err := ta.db.QueryRow(ctxTimeout, query).Scan(&result.Min, &result.Max)
+	if err != nil {
+		return etl.MaxMinColumnResult{}, err
+	}
+
+	return result, nil
+}
+
 func (ta *MssqlTableAnalyzer) CalculatePartitionRanges(
 	ctx context.Context,
 	tableInfo config.TableInfo,