refactor: update RangeConfig to use pointers for min and max; adjust partition calculation logic to handle nil values

internal/app/etl/table_analyzers/mssql.go

@@ -224,12 +224,37 @@ func (ta *MssqlTableAnalyzer) CalculatePartitionRanges(
 	tableInfo config.TableInfo,
 	partitionColumn string,
 	maxPartitions int64,
+	rangeConstraint config.RangeConfig,
 ) ([]models.Partition, error) {
+	whereClause := ""
+	args := []any{sql.Named("maxPartitions", maxPartitions)}
+
+	if rangeConstraint.Min != nil || rangeConstraint.Max != nil {
+		var conditions []string
+		if rangeConstraint.Min != nil {
+			minOp := ">"
+			if rangeConstraint.IsMinInclusive {
+				minOp = ">="
+			}
+			conditions = append(conditions, fmt.Sprintf("[%s] %s @rangeMin", partitionColumn, minOp))
+			args = append(args, sql.Named("rangeMin", *rangeConstraint.Min))
+		}
+		if rangeConstraint.Max != nil {
+			maxOp := "<"
+			if rangeConstraint.IsMaxInclusive {
+				maxOp = "<="
+			}
+			conditions = append(conditions, fmt.Sprintf("[%s] %s @rangeMax", partitionColumn, maxOp))
+			args = append(args, sql.Named("rangeMax", *rangeConstraint.Max))
+		}
+		whereClause = "WHERE " + strings.Join(conditions, " AND ")
+	}
+
 	query := fmt.Sprintf(`
 SELECT
 	MIN([%s]) AS lower_limit,
 	MAX([%s]) AS upper_limit
-FROM (SELECT [%s], NTILE(@maxPartitions) OVER (ORDER BY [%s]) AS batch_id FROM [%s].[%s]) AS T
+FROM (SELECT [%s], NTILE(@maxPartitions) OVER (ORDER BY [%s]) AS batch_id FROM [%s].[%s] %s) AS T
 GROUP BY batch_id
 ORDER BY batch_id`,
 		partitionColumn,
@@ -237,12 +262,13 @@ ORDER BY batch_id`,
 		partitionColumn,
 		partitionColumn,
 		tableInfo.Schema,
-		tableInfo.Table)
+		tableInfo.Table,
+		whereClause)
 
 	ctxTimeout, cancel := context.WithTimeout(ctx, 1*time.Minute)
 	defer cancel()
 
-	rows, err := ta.db.Query(ctxTimeout, query, sql.Named("maxPartitions", maxPartitions))
+	rows, err := ta.db.Query(ctxTimeout, query, args...)
 	if err != nil {
 		return nil, err
 	}