有關加入連接的ORACLE SQL查詢

Question

我有以下問題。 我目前正在嘗試從數據庫中的許多不同表中返回信息。 過程是將一個活動添加到系統中，理論上應該遵循某種類型的協議。 但是，有時活動並未遵循預期的協議，我想確定這種情況。

我目前有一個查詢（如下所示），它返回看起來像這樣的數據（從實際查詢中簡化）：

ID  Activity  Agreement     Agreement Type
1   X         Budgets       Payment
2   X
3   X         Budgets

數據應如下所示：

ID  Activity  Agreement     Agreement Type
1   X         Budgets       Payment
2   X
3   X         

基本上，如果沒有協議類型的付款，我不希望協議顯示（但我仍然希望看到活動）。 ID用於將活動加入協議，但協議和協議類型來自連接在描述ID上的單獨表。

SELECT  O_ACTIVITIES.ACT_SUBJECT_ID as "ID",
        initcap(olm_bo.get_per_name(O_ACTIVITIES.ACT_SUBJECT_ID)) as "Name",
        O_ACTIVITIES.ACT_ID as "Activity ID",
        initcap(O_ACTIVITY_TYPES.ACT_DESC) as "Activity Type",
        O_ACTIVITIES.ACT_REQUESTED_DATE as "Start Date",
        case when olm_bo.get_ref_desc(O_ACTIVITIES.ACT_STATUS,'ACTIVITY_STATUS') = 'Newly generated' 
                  then null 
                  else O_ACTIVITIES.ACT_STATUS_DATE 
             end as "End Date",
        olm_bo.get_ref_desc(O_ACTIVITIES.ACT_STATUS,'ACTIVITY_STATUS') as "Status",
        O_ACTIVITIES.ACT_CREATED_BY as "Created by",
        O_AGREEMENT_DETAILS.ADE_ID as "Agreement ID",
        initcap(olm_bo.get_sty_name(O_AGREEMENT_DETAILS.ADE_STY_ID)) as "Service Type",
        initcap(olm_bo.get_sty_name(O_SERVICE_ELEMENTS.SEL_STY_CHILD_ID)) as "Service Element",
        O_AGREEMENT_DETAILS.ADE_START_DATE as "Agreement Start",
        O_AGREEMENT_DETAILS.ADE_END_DATE as "Agreement End",
        O_AGREEMENT_DETAILS.ADE_ENTERED_BY as "Entered by"
FROM O_ACTIVITIES
LEFT JOIN O_ACTIVITY_TYPES 
       ON O_ACTIVITY_TYPES.ACT_CLASS= O_ACTIVITIES.ACT_CLASS and 
          O_ACTIVITY_TYPES.ACT_TYPE=O_ACTIVITIES.ACT_TYPE AND
          initcap(O_ACTIVITY_TYPES.ACT_DESC)  =  'X'
LEFT OUTER JOIN O_AGREEMENT_DETAILS 
       ON O_AGREEMENT_DETAILS.ADE_SUBJECT_ID=O_ACTIVITIES.ACT_SUBJECT_ID  AND 
          initcap(olm_bo.get_sty_name(O_AGREEMENT_DETAILS.ADE_STY_ID)) IN ('Budgets') AND 
          O_AGREEMENT_DETAILS.ADE_START_DATE >= O_ACTIVITIES.ACT_REQUESTED_DATE
LEFT JOIN O_SERVICE_ELEMENTS 
       ON O_AGREEMENT_DETAILS.ADE_SEL_ID=O_SERVICE_ELEMENTS.SEL_ID AND
          initcap(olm_bo.get_sty_name(O_SERVICE_ELEMENTS.SEL_STY_CHILD_ID)) IN ('Payment')
WHERE (O_ACTIVITIES.ACT_SYSTEM_IND IS NULL and 
      NVL(O_ACTIVITIES.ACT_REC_TYPE,'???') NOT IN ('Y')  ) AND
      initcap(O_ACTIVITY_TYPES.ACT_DESC)  =  'X'

問題是包含協議類型描述的服務元素表是從協議表中分離出來的。 我可以使用協議類型代碼（實際上將協議類型加入協議表），但是，我真的只想知道我是否可以在協議表和協議類型表之間實現內部連接，這不會影響活動表。

任何指針和建議都表示贊賞，希望我已經充分解釋了自己。

Answer 1

最簡單的方法（由於它是一個怪物SQL）是包裝它並使用case語句，例如

SELECT ID, Activity, Case When Agreement_Type IS NULL THEN NULL ELSE Agreement END, Agreement_Type
FROM
(All the original SQL goes in here)

因此，基本上圍繞整個第一個SQL運行另一個SQL，因為它比選擇通過更容易，順便說一下，在列名中避免使用空格總是一個好主意，所以我在這種情況下使用了_。

Answer 2

嘗試：

SELECT  O_ACTIVITIES.ACT_SUBJECT_ID as "ID",
        initcap(olm_bo.get_per_name(O_ACTIVITIES.ACT_SUBJECT_ID)) as "Name",
        O_ACTIVITIES.ACT_ID as "Activity ID",
        initcap(O_ACTIVITY_TYPES.ACT_DESC) as "Activity Type",
        O_ACTIVITIES.ACT_REQUESTED_DATE as "Start Date",
        case when olm_bo.get_ref_desc(O_ACTIVITIES.ACT_STATUS,'ACTIVITY_STATUS') = 'Newly generated' 
                  then null 
                  else O_ACTIVITIES.ACT_STATUS_DATE 
             end as "End Date",
        olm_bo.get_ref_desc(O_ACTIVITIES.ACT_STATUS,'ACTIVITY_STATUS') as "Status",
        O_ACTIVITIES.ACT_CREATED_BY as "Created by",
        O_AGREEMENT_DETAILS.ADE_ID as "Agreement ID",
        initcap(olm_bo.get_sty_name(O_AGREEMENT_DETAILS.ADE_STY_ID)) as "Service Type",
        initcap(olm_bo.get_sty_name(O_SERVICE_ELEMENTS.SEL_STY_CHILD_ID)) as "Service Element",
        O_AGREEMENT_DETAILS.ADE_START_DATE as "Agreement Start",
        O_AGREEMENT_DETAILS.ADE_END_DATE as "Agreement End",
        O_AGREEMENT_DETAILS.ADE_ENTERED_BY as "Entered by"
FROM O_ACTIVITIES
LEFT JOIN O_ACTIVITY_TYPES 
       ON O_ACTIVITY_TYPES.ACT_CLASS= O_ACTIVITIES.ACT_CLASS and 
          O_ACTIVITY_TYPES.ACT_TYPE=O_ACTIVITIES.ACT_TYPE AND
          initcap(O_ACTIVITY_TYPES.ACT_DESC)  =  'X'
LEFT JOIN O_AGREEMENT_DETAILS 
          JOIN O_SERVICE_ELEMENTS 
            ON O_AGREEMENT_DETAILS.ADE_SEL_ID=O_SERVICE_ELEMENTS.SEL_ID AND
               initcap(olm_bo.get_sty_name(O_SERVICE_ELEMENTS.SEL_STY_CHILD_ID)) IN ('Payment')
       ON O_AGREEMENT_DETAILS.ADE_SUBJECT_ID=O_ACTIVITIES.ACT_SUBJECT_ID  AND 
          initcap(olm_bo.get_sty_name(O_AGREEMENT_DETAILS.ADE_STY_ID)) IN ('Budgets') AND 
          O_AGREEMENT_DETAILS.ADE_START_DATE >= O_ACTIVITIES.ACT_REQUESTED_DATE
WHERE (O_ACTIVITIES.ACT_SYSTEM_IND IS NULL and 
      NVL(O_ACTIVITIES.ACT_REC_TYPE,'???') NOT IN ('Y')  ) AND
      initcap(O_ACTIVITY_TYPES.ACT_DESC)  =  'X'