如果没有数据则跳过创建 JSON_OBJECT

Question

我正在创建一个具有多个层的 JSON_OBJECT，如果没有匹配的数据，则不应创建 JSON_OBJECT。在示例中，我将展示如何在没有数据的情况下通过跳过一个级别来创建它，但我希望有一种更好、更简单的方法来做到这一点，因为我无法通过这种方式来处理当前的问题。此 JSON 的结束位置无法处理 null JSON_OBJECTS，因此他们希望将它们从文件中排除。

这是一些示例数据： 健康）状况：

行动：

如您所见，其中一个条件没有匹配的操作。 这就是我当前创建 JSON 的方式，它不会根据需要删除额外的 JSON_OBJECT，但确实显示了我如何在需要外语时创建一个级别。

     With      
                                           
-- Create All of the (actions)         
 fAction1 as (                                 
  Select CONCCD, CONDID,     
      Case when PADSecLangCode = '' then   
    json_object(                                 
     'actionID'            : trim(ACTID),      
     'actionDescription' : trim(DESC),    
    'active'                 : ACTIVE)
  Else                                                    
  json_object(              
       'actionID'          : trim(ACTID),      
     'actionDescription' : trim(DESC),    
     'active'                : ACTIVE,     
      'recordTexts' : json_object( 
       'recordText' : json_array( json_object( 
         'languageID'        : trim(PADSecLangCode), 
         'actionDescription' : trim(DESCF),    
         'active'                : ACTIVE )))     )     
  End          
               as sAction1                               
   From PADWCA) 


-- Create All of the Conditions (conditions/actions)         
 , fCondition1 as (                                 
  Select CONCCD,   
   Case when PADSecLangCode = '' then   
    json_object(                                 
     'conditionID'            : trim(CONDID),      
     'conditionDescription' : trim(DESC),    
    'active'                     : ACTIVE,
        'actions' : json_object(
          'action' : json_array( 
         (Select sAction1  
          From fAction1 a
          Where a.CONCCD = c.CONCCD and a.CONDID = c.CONDID
                            ) format json    
                              ) format json  
                                ) format json )       
  Else                                                    
  json_object(    
     'conditionID'            : trim(CONDID),      
     'conditionDescription' : trim(DESC),    
    'active'                     : ACTIVE,
    'recordTexts' : json_object( 
     'recordText' : json_array( json_object( 
       'languageID'             : trim(PADSecLangCode), 
       'conditionDescription' : trim(DESCF),    
          'active'                 : ACTIVE ))),     
        'actions' : json_object(
          'action' : json_array( 
         (Select sAction1  
          From fAction1 a
          Where a.CONCCD = c.CONCCD and a.CONDID = c.CONDID
                        ) format json    
                          ) format json  
                            ) format json   )
End
               as sCondition1  
   From PADWCC  c)  

-- 在条件/动作周围创建一个包装器 , fCondition2 为 (选择 json_object( '条件': json_arrayagg( sCondition1 格式 json)) 作为 sCondition2 来自 fCondition1)

-- 创建最终结果
选择 json_object( '条件' : sCondition2 格式 json) 来自 fCondition2;

这是我目前得到的结果：

{
"conditions": {
    "condition": [
        {
            "conditionID": "038-00068-C32",
            "conditionDescription": "Exclusion service repairs were made to the following areas:",
            "active": "false",
            "recordTexts": {
                "recordText": [
                    {
                        "languageID": "FR",
                        "conditionDescription": "Service de réparations d'exclusion ont été faites aux domaines suivants:",
                        "active": "false"
                    }
                ]
            },
            "actions": {
                "action": []
            }
        },
        {
            "conditionID": "020-00050-C26",
            "conditionDescription": "The area was very clean and in excellent condition!",
            "active": "false",
            "recordTexts": {
                "recordText": [
                    {
                        "languageID": "FR",
                        "conditionDescription": "La zone était très propre et en excellent état!",
                        "active": "false"
                    }
                ]
            },
            "actions": {
                "action": [
                    {
                        "actionID": "001-051-C26",
                        "actionDescription": "Please thank everyone who cleaned the area!",
                        "active": "false",
                        "recordTexts": {
                            "recordText": [
                                {
                                    "languageID": "FR",
                                    "actionDescription": "'il vous plaît remercier tous ceux qui nettoyé la zone!",
                                    "active": "false"
                                }
                            ]
                        }
                    }
                ]
            }
        }
    ]
}

}

这是我想要得到的结果：

{
"conditions": {
    "condition": [
        {
            "conditionID": "038-00068-C32",
            "conditionDescription": "Exclusion service repairs were made to the following areas:",
            "active": "false",
            "recordTexts": {
                "recordText": [
                    {
                        "languageID": "FR",
                        "conditionDescription": "Service de réparations d'exclusion ont été faites aux domaines suivants:",
                        "active": "false"
                    }
                ]
            },
        },
        {
            "conditionID": "020-00050-C26",
            "conditionDescription": "The area was very clean and in excellent condition!",
            "active": "false",
            "recordTexts": {
                "recordText": [
                    {
                        "languageID": "FR",
                        "conditionDescription": "La zone était très propre et en excellent état!",
                        "active": "false"
                    }
                ]
            },
            "actions": {
                "action": [
                    {
                        "actionID": "001-051-C26",
                        "actionDescription": "Please thank everyone who cleaned the area!",
                        "active": "false",
                        "recordTexts": {
                            "recordText": [
                                {
                                    "languageID": "FR",
                                    "actionDescription": "'il vous plaît remercier tous ceux qui nettoyé la zone!",
                                    "active": "false"
                                }
                            ]
                        }
                    }
                ]
            }
        }
    ]
}

}

Answer 1

编辑：我更新了答案以满足您的要求。这让我回到你原来的问题：我用nullif(xxx, json_object())

所以

'actions' : actionsArray format json

现在是

'actions' : nullif(json_object( /* null if value equals empty object */
                    'action' : actionsArray format json
                    absent on null
                    ), json_object()) format json

关于您的第二条评论，我使用了值，因为它在没有数据时返回“{}”，但您可以肯定地使用 select into 你可以使用

values ... into :pgmvar
-- or 
select ... into :pgmvar from ...

抱歉，您的代码不太容易阅读。我重写了它，因为我认为我已经完成了。 结果的结构有点改变，因为我不明白为什么 recordTexts 对象中的 recordText 数组，对于 action/actions 相同：

with
-- Test data, conditions
PADWCC (CONCCD, CONDID, DESC, DESCF, ACTIVE) as (
    values
    (1, '038-00068-C32','Exclusion service repairs were made to the following areas:', 'Service de réparations d''exclusion ont été faites aux domaines suivants:', 'false'),
    (1, '020-00050-C26','The area was very clean and in excellent condition!', 'La zone était très propre et en excellent état!', 'false')
),
-- Test data, actions
PADWCA (CONCCD, CONDID, ACTID, DESC, DESCF, ACTIVE) as (
    values
    (1 ,'020-00050-C26', '001-051-C26','Please thank everyone who cleaned the area!', 'S''il vous plaît remercier tous ceux qui nettoyé la zone!', 'false')
    --,(1 ,'020-00050-C26', 'otheraction','otheraction', 'autre action', 'false')
),
-- Step 1: create an array of translations for each action (with only one translation inside)
actionsTranslations as (
    select
        CONCCD,
        CONDID,
        ACTID,
        json_arrayagg(
            json_object(
                'languageID' : languageID,
                'actionDescription' : actionDescription,
                'active' : active
                )
            ) 
        as recordTexts
    from
        PADWCA
        cross join lateral ( -- Construct a list of text(s) from PADWCA.DESCF
            values
            ('FR', DESCF)
        ) as texts(languageID, actionDescription)
    where languageID = PADSecLangCode
    group by CONCCD, CONDID, ACTID
),
-- Step 2: Create an object for each action
actionObjects as (
    select
        CONCCD,
        CONDID,
        ACTID,
        json_object(
                'actionID' : trim(PADWCA.ACTID),
                'actionDescription' : trim(DESC),
                'active' : active,
                'recordTexts' : nullif(json_object(
                    'recordText' : recordTexts format json absent on null
                    ), json_object()) format json
                absent on null -- no recordTexts key if null
            ) actionObject
    from
        PADWCA
        left join actionsTranslations using(conccd, condid, actid)
),
-- Step 3: Create an array of actions for each condition
actions as (
    select CONCCD, CONDID, JSON_ARRAYAGG(actionObject format json) as actionsArray from actionObjects group by CONCCD, CONDID
),
-- Step 4: create an array of translations for each condition (with only one translation inside)
conditionsTranslations as (
    select
        CONCCD,
        CONDID,
        json_arrayagg(
            json_object(
                'languageID' : languageID,
                'conditionDescription' : conditionDescription,
                'active' : active
                )
            ) 
        as recordTexts
    from
        PADWCC
        cross join lateral (
            values
            ('FR', DESCF)
        ) as texts(languageID, conditionDescription)
    where languageID = PADSecLangCode
    group by CONCCD, CONDID
),
-- Step 5: Create an object for each condition
conditionObjects as (
    select
        ca.CONCCD,
        ca.CONDID,
        json_object(
                'conditionID' : trim(ca.CONDID),
                'conditionDescription' : trim(DESC),
                'active' : active,
                'recordTexts' : nullif(json_object(
                    'recordText' : recordTexts format json absent on null
                    ), json_object()) format json,
                'actions' : nullif(json_object(
                    'action' : actionsArray format json
                    absent on null
                    ), json_object()) format json
                absent on null -- absent on null applies to every key of the object so recordTexts AND actions
            ) conditionObject
    from
        PADWCC ca
        left join conditionsTranslations ct on (ct.conccd, ct.condid) = (ca.conccd, ca.condid)
        left join actions ac on (ac.conccd, ac.condid) = (ca.conccd, ca.condid)
),
-- Step 6: Create an array of conditions for each CONCCD
conditions as (
    select CONCCD, JSON_ARRAYAGG(conditionObject format json) as array from conditionObjects group by CONCCD
)
-- Wrap output in an object
values json_object('conditions' : nullif(json_object('condition' : (select conditions.array from conditions where conccd = 1) format json absent on null), json_object()) format json absent on null);
--or
--select json_object('conditions' : nullif(json_object('condition' : conditions.array format json absent on null), json_object()) format json absent on null) from conditions where conccd = 2;

给予

{
    "conditions": {
        "condition": [
            {
                "conditionID": "038-00068-C32",
                "conditionDescription": "Exclusion service repairs were made to the following areas:",
                "active": "false",
                "recordTexts": {
                    "recordText": [
                        {
                            "languageID": "FR",
                            "conditionDescription": "Service de réparations d'exclusion ont été faites aux domaines suivants:",
                            "active": "false"
                        }
                    ]
                }
            },
            {
                "conditionID": "020-00050-C26",
                "conditionDescription": "The area was very clean and in excellent condition!",
                "active": "false",
                "recordTexts": {
                    "recordText": [
                        {
                            "languageID": "FR",
                            "conditionDescription": "La zone était très propre et en excellent état!",
                            "active": "false"
                        }
                    ]
                },
                "actions": {
                    "action": [
                        {
                            "actionID": "001-051-C26",
                            "actionDescription": "Please thank everyone who cleaned the area!",
                            "active": "false",
                            "recordTexts": {
                                "recordText": [
                                    {
                                        "languageID": "FR",
                                        "actionDescription": "S'il vous plaît remercier tous ceux qui nettoyé la zone!",
                                        "active": "false"
                                    }
                                ]
                            }
                        }
                    ]
                }
            }
        ]
    }
}