理解 DB2 中的复杂 SP

我需要对具有大量复杂 XML 函数的 SP 进行更改

Declare ResultCsr2 Cursor For
       WITH
       MDI_BOM_COMP(PROD_ID,SITE_ID, xml ) AS (
       SELECT TC401F.T41PID,TC401F.T41SID,
        XMLSERIALIZE(
         XMLAGG(
          XMLELEMENT( NAME "MDI_BOM_COMP",
           XMLFOREST(
                     trim(TC401F.T41CTY) AS COMPONENT_TYPE,
                     TC401F.T41LNO AS COMP_NUM,
                     trim(TC401F.T41CTO) AS CTRY_OF_ORIGIN,
                     trim(TC401F.T41DSC) AS DESCRIPTION,
                     TC401F.T41EFR AS EFFECTIVE_FROM,
                     TC401F.T41EFT AS EFFECTIVE_TO,
                     trim(TC401F.T41MID) AS MANUFACTURER_ID,
                     trim(TC401F.T41MOC) AS MANUFACTURER_ORG_CODE,
                     trim(TC401F.T41CNO) AS PROD_ID,
                     trim(TC401F.T41POC) AS PROD_ORG_CODE,
                     TC401F.T41QPR AS QTY_PER,
                     trim(TC401F.T41SBI) AS SUB_BOM_ID,
                     trim(TC401F.T41SBO) AS SUB_BOM_ORG_CODE,       --ADB01
                     trim(TC401F.T41VID) AS SUPPLIER_ID,
                     trim(TC401F.T41SOC) AS SUPPLIER_ORG_CODE,
                     TC401F.T41UCT AS UNIT_COST
               )
              )
             ) AS CLOB(1M)
            )
             FROM TC401F TC401F
             GROUP BY T41PID,T41SID
            )

       SELECT
       RowNum, '<BOM_INBOUND>' ||
        XMLSERIALIZE (
         XMLELEMENT(NAME "INTEGRATION_MESSAGE_CONTROL",
          XMLFOREST(
                    'FULL_UPDATE' as ACTION,
                    'POLARIS' as COMPANY_CODE,
                    TRIM(TC400F.T40OCD) as ORG_CODE,
                    '5' as PRIORITY,
                    'INBOUND_ENTITY_INTEGRATION' as MESSAGE_TYPE,
                    'POLARIS_INTEGRATION' as USERID,
                    'TA' as RECEIVER,
                    HEX(Generate_Unique()) as SOURCE_SYSTEM_TOKEN
                    ),
                      XMLELEMENT(NAME "BUS_KEY",
                       XMLFOREST(
                        TRIM(TC400F.T40BID) as BOM_ID,
                        TRIM(TC400F.T40OCD) as ORG_CODE
                       )
                      )
                     ) AS VARCHAR(1000)
                    )
            || '<MDI_BOM>' ||
              XMLSERIALIZE (
               XMLFOREST(

                 TRIM(TC400F.T40ATP) AS ASSEMBLY_TYPE,
                 TRIM(TC400F.T40BID) AS BOM_ID,
                 TRIM(TC400F.T40CCD) AS CURRENCY_CODE,
                 TC400F.T40DPC AS DIRECT_PROCESSING_COST,
                 TC400F.T40EFD AS EFFECTIVE_FROM,
                 TC400F.T40EFT AS EFFECTIVE_TO,
                 TRIM(TC400F.T40MID) AS MANUFACTURER_ID,
                 TRIM(TC400F.T40MOC) AS MANUFACTURER_ORG_CODE,
                 TRIM(TC400F.T40OCD) AS ORG_CODE,
                 TRIM(TC400F.T40PRF) AS PROD_FAMILY,
                 TRIM(TC400F.T40PID) AS PROD_ID,
                 TRIM(TC400F.T40POC) AS PROD_ORG_CODE,
                 TRIM(TC400F.T40ISA) AS IS_ACTIVE,
                 TRIM(TC400F.T40VID) AS SUPPLIER_ID,
                 TRIM(TC400F.T40SOC) AS SUPPLIER_ORG_CODE,
                 TRIM(TC400F.T40PSF) AS PROD_SUB_FAMILY,
                 CASE TRIM(TC400F.T40PML)
                    WHEN '' THEN TRIM(TC400F.T40PML)
                    ELSE TRIM(TC400F.T40PML) || '~' || TRIM(TC403F.T43MDD)
                   END    AS PROD_MODEL

                  ) AS VARCHAR(3000)
                 )
            || IFNULL(MBC.xml, '') ||
               XMLSERIALIZE (
                 XMLFOREST(
                   XMLFOREST(
                     TRIM(TC400F.T40CCD) AS CURRENCY_CODE,
                     TC400F.T40PRI AS PRICE,
                     TRIM(TC400F.T40PTY) AS PRICE_TYPE
                       ) AS MDI_BOM_PRICE,
                    XMLFOREST(
                      TRIM(TC400F.T40CCD) AS CURRENCY_CODE,
                      TRIM(TC400F.T40PRI) AS PRICE,
                      'TRANSACTION_VALUE' AS PRICE_TYPE
                      ) AS MDI_BOM_PRICE,
                    XMLFOREST(
                      TRIM(TC400F.T40INA) AS INCLUDE_IN_AVERAGING

                       ) AS MDI_BOM_IMPL_BOM_PROD_FAMILY_AUTOMOBILES

                      ) AS VARCHAR(3000)
                    )
                  || '</MDI_BOM>' ||
                  '</BOM_INBOUND>' XML
                     FROM (
                            SELECT
                            ROW_NUMBER() OVER (
                                   ORDER BY T40STS
                                   ,T40SID
                                   ,T40BID
                            ) AS RowNum
                            ,t.*
                            FROM TC400F t
                     ) TC400F

                     LEFT OUTER JOIN MDI_BOM_COMP MBC
                     ON TC400F.T40SID = MBC.SITE_ID
                     AND TC400F.T40PID = MBC.PROD_ID
                     LEFT OUTER JOIN TC403F TC403F
                      ON TC400F.T40PML <> ''
                      AND TC400F.T40PML = TC403F.T43MDL
                     WHERE TC400F.T40STS = '10'
                       AND TC400F.RowNUM BETWEEN
                         (P_STARTROW + (P_PAGENOS - 1) * P_NBROFRCDS)
                         AND (P_STARTROW  + (P_PAGENOS - 1) * P_NBROFRCDS  +
                              P_NBROFRCDS - 1);

上面给出的是我正在努力理解的 SP 代码中的游标声明。第一个 WITH 本身似乎很神秘。我已经将它与临时表名一起使用，但这是第一次，我看到这种似乎是 SP 或 UDF 的东西？有人可以指导我如何理解和理解这一切吗？

进一步补充这个问题，这里的实际要求是在 XML 中排列数据，这样那些填充了 TC401F.T41SBI 字段的记录应该出现在 XML 输出的开头。

在代码中选择此字段如下：

trim(TC401F.T41SBI) AS SUB_BOM_ID. 如果此字段不为空，则它应首先出现在 XML 中，并且任何具有此字段值空白的记录应仅出现在其后。这样做的最佳方法是什么？以任何方式使用 ORDER BY 似乎并没有真正的帮助，因为 XML 实际上是通过某些函数创建的，而排序依据不会影响项目在 XML 中的排列方式。我能想到的一种方法是使用 where 子句，其中TC401F.T41SBI <> ''首先将那些记录附加到 whereTC401F.T41SBI = ''