将 SQL Server 存储过程转换为 Java

Question

I'm migrating old reporting systems to a modern Java code base and stumbled upon Microsoft Sql Server stored procedure that generated table with dates (Year, Period, WeekStarting, WeekEnding). I need to migrate this code into Java and make it dynamic, as opposed to generate it a table and take up space in the DB.

Seeking a help from a Sql Server expert to help me understand how those dates are derived, and especially numbers in the Period column

USE [Reporting]
GO

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

CREATE PROCEDURE [dbo].[GenDataforPeriodsTable]
    @enddate VARCHAR(10)
AS
    DECLARE @startdate VARCHAR(10)
BEGIN
    SET NOCOUNT ON; 

    SELECT @startdate = DATEADD(DAY, 1, MAX(WeekEnding)) FROM Periods;

    WITH CTE_DatesTable
    AS
    (
      SELECT CAST(@startdate as date) AS tempdate
      UNION ALL
      SELECT DATEADD(dd, 1, tempdate)
      FROM CTE_DatesTable
      WHERE DATEADD(dd, 1, tempdate) <= @enddate
    )
    INSERT INTO Periods (YEAR, Period, WeekStarting, WeekEnding)
    SELECT YEAR(tempdate) as Year, MONTH(DATEADD(DAY, -3, tempdate)) as Period, 
            DATEADD(DAY, -6, tempdate) as WeekStarting, tempdate as WeekEnding 
    FROM CTE_DatesTable 
    WHERE DATENAME(weekday, tempdate) = 'SUNDAY'        
    OPTION (MAXRECURSION 0)

END
GO

it generates table like this:

Answer 1

Java 8 code:

import static java.time.DayOfWeek.SUNDAY;
import static java.time.temporal.TemporalAdjusters.nextOrSame;

import java.time.LocalDate;

static void genDataforPeriodsTable(LocalDate endDate) {
    String sql = "SELECT MAX(WeekEnding) FROM Periods";
    LocalDate maxWeekEnding = /* Result of running query */;
    genDataforPeriodsTable(maxWeekEnding.plusDays(1), endDate);
}

static void genDataforPeriodsTable(LocalDate startDate, LocalDate endDate) {
    System.out.println("Year Period WeekStarting WeekEnding");
    System.out.println("==== ====== ============ ==========");
    for (LocalDate tempdate = startDate.with(nextOrSame(SUNDAY));
                   tempdate.compareTo(endDate) <= 0;
                   tempdate = tempdate.plusDays(7)) {
        int year = tempdate.getYear();
        int period = tempdate.minusDays(3).getMonthValue();
        LocalDate weekStarting = tempdate.minusDays(6);
        LocalDate weekEnding = tempdate;
        System.out.printf("%4d %-6d %-12s %s%n", year, period, weekStarting, weekEnding);
    }
}

Test

genDataforPeriodsTable(LocalDate.of(2019, 10, 25), LocalDate.of(2020, 5, 5));

Output

The output here is in reverse order of what you included, but the data is the same, except for that start date error in the first week of 2020, as commented by Lothar .

Year Period WeekStarting WeekEnding
==== ====== ============ ==========
2019 10     2019-10-21   2019-10-27
2019 10     2019-10-28   2019-11-03
2019 11     2019-11-04   2019-11-10
2019 11     2019-11-11   2019-11-17
2019 11     2019-11-18   2019-11-24
2019 11     2019-11-25   2019-12-01
2019 12     2019-12-02   2019-12-08
2019 12     2019-12-09   2019-12-15
2019 12     2019-12-16   2019-12-22
2019 12     2019-12-23   2019-12-29
2020 1      2019-12-30   2020-01-05
2020 1      2020-01-06   2020-01-12
2020 1      2020-01-13   2020-01-19
2020 1      2020-01-20   2020-01-26
2020 1      2020-01-27   2020-02-02
2020 2      2020-02-03   2020-02-09
2020 2      2020-02-10   2020-02-16
2020 2      2020-02-17   2020-02-23
2020 2      2020-02-24   2020-03-01
2020 3      2020-03-02   2020-03-08
2020 3      2020-03-09   2020-03-15
2020 3      2020-03-16   2020-03-22
2020 3      2020-03-23   2020-03-29
2020 4      2020-03-30   2020-04-05
2020 4      2020-04-06   2020-04-12
2020 4      2020-04-13   2020-04-19
2020 4      2020-04-20   2020-04-26
2020 4      2020-04-27   2020-05-03