SQL 根据定义的优先级查找匹配记录

Question

我必须构建一个逻辑来更新一列 SC_LEVI_LVL IN GCC_MAST.CLNT_MAST 基于以下条件找到的匹配项：

（我只是在看select子句，稍后我会使用informatica中的更新策略更新它）

需要在三个表上进行连接：

对于优先级 1，需要在以下两个表上进行连接：

GCC_LANDING.CB_AT_LIS CB
    GCC_MAST.CLNT_MAST TM

对于优先级 2，需要在以下 3 个表上进行连接：

GCC_LANDING.CB_AT_LIS CB
GCC_MAST.CLNT_MAST TM
GCC_LANDING.GRID_MATRIX GM

优先级 1：

CB.REL_COUNTRY=TM.REL_COUNTRY
AND CB.GRID=TM.GRID
WHERE TM.SCH_LEG_ENTY NOT LIKE '%BASE%'
AND CB.LAT='Y'

预期结果：

优先级 2：

CB.GRID=GM.GRID
AND CB.REL_COUNTRY=TM.REL_COUNTRY
AND GM.SUR_GRD=TM.GRID
WHERE TM.SCH_LEG_ENTY NOT LIKE '%BASE%'
AND TM.CUS LIKE '% BGM%'
AND CB.GRID <> TM.GRID
AND TM.CUST_FLG='N'

预期结果：

（如果多条记录发现分区 ROW_NUMBER=1）

我能想到的就是将它们全部放在一个查询中，并在所有表上进行联接（合并 P1 和 P2），然后在开头使用 case 语句。但是，我认为这不是正确的方法。

有人可以指导我如何进行吗？我对此很陌生，会用我想出的任何东西更新 post。

期望的结果应该是 SC_LEVI_LVL IN GCC_MAST.CLNT_MAST 的值，首先基于 P1，如果 P1 不匹配，则 P2

谢谢！

Answer 1

-- here is the combination of the two - priority_one and priority_two
WITH
    landing As
        (
            Select 'NZ' "REL_COUNTRY", 12345 "GRID", 'Y' "LAT", 'ABC' "SC_LEVI_LVL" From Dual
          UNION
            Select 'MO' "REL_COUNTRY", 44444 "GRID", 'Y' "LAT", 'XYZ' "SC_LEVI_LVL" From Dual
          UNION
            Select 'PH' "REL_COUNTRY", 55555 "GRID", 'Y' "LAT", 'ERT' "SC_LEVI_LVL" From Dual
          UNION
            Select 'PH' "REL_COUNTRY", 78786 "GRID", 'Y' "LAT", 'ERT' "SC_LEVI_LVL" From Dual
        ),
    clnt As
        (
            Select 'ZA' "REL_COUNTRY", 56565 "GRID", 'HBASEU' "SCH_LEG_ENTY", 'TFGD' "CUS", 'N' "CUST_FLG" From Dual
          UNION
            Select 'NZ' "REL_COUNTRY", 12345 "GRID", 'DFGT' "SCH_LEG_ENTY", 'HBGM' "CUS", 'N' "CUST_FLG" From Dual
          UNION
            Select 'MO' "REL_COUNTRY", 44444 "GRID", 'DFGTU' "SCH_LEG_ENTY", 'HBGM' "CUS", 'N' "CUST_FLG" From Dual
          UNION
            Select 'PH' "REL_COUNTRY", 99999 "GRID", 'DFGTU' "SCH_LEG_ENTY", 'HBGM' "CUS", 'N' "CUST_FLG" From Dual
        ),
    matrix As
        ( Select 99999 "SUR_GRID", 78786 "GRID" From Dual ),
    priority_one As 
        (
            SELECT
                'ONE' "WHICH_ONE",
                cb.REL_COUNTRY "REL_COUNTRY",
                cb.GRID "GRID",
                cb.LAT "LAT",
                cb.SC_LEVI_LVL "SC_LEVI_LVL"
            FROM
                landing cb
            INNER JOIN
                clnt tm ON(CB.REL_COUNTRY=TM.REL_COUNTRY And cb.GRID = tm.GRID)
            WHERE 
                tm.SCH_LEG_ENTY NOT LIKE '%BASE%' And 
                CB.LAT = 'Y'
        ),
    priority_two As
        (
            SELECT
                'TWO' "WHICH_ONE",
                cb.REL_COUNTRY "REL_COUNTRY",
                cb.GRID "GRID",
                cb.LAT "LAT",
                cb.SC_LEVI_LVL "SC_LEVI_LVL"
            FROM
                matrix gm
            INNER JOIN
                landing cb ON(cb.GRID = gm.GRID)
            INNER JOIN
                clnt tm ON(cb.REL_COUNTRY = tm.REL_COUNTRY And gm.SUR_GRID = tm.GRID)
            WHERE 
                tm.SCH_LEG_ENTY NOT LIKE '%BASE%' And 
                cb.GRID <> tm.GRID And 
                tm.CUST_FLG = 'N'
        )
    SELECT WHICH_ONE, REL_COUNTRY, GRID, LAT, SC_LEVI_LVL From priority_one 
  UNION ALL 
    SELECT WHICH_ONE, REL_COUNTRY, GRID, LAT, SC_LEVI_LVL FROM priority_two
--
-- Result:
--
-- WHICH_ONE REL_COUNTRY       GRID LAT SC_LEVI_LVL
-- ONE       MO               44444 Y   XYZ       
-- ONE       NZ               12345 Y   ABC       
-- TWO       PH               78786 Y   ERT

SQL 根据定义的优先级查找匹配记录

SQL to find the match record based on the priority defined

sql

database

oracle