PostgreSQL-查询JSONB数据中键的第n个实例的值

很抱歉，此页的格式设置错误。有太多的文字，无法创建一个可读的表格，所以请容忍我

我有一张叫做“谢绝”的桌子。它有两列：“id”和“dec_原因”

对于id=34254，这是JSONB格式的“dec_Reasions”值：

[
    {
        "id": 94748,
        "reason": "Lead Fico Threshold is not Greater Than Or Equal To 500",
        "created_at": "2019-05-02T07:57:59.706448",
        "decline_code": "fico_too_low",
        "leaf_node_id": 7,
        "decision_type": "credit",
        "triggers_noaa": true,
        "general_description": "FICO score is too low"
    },
    {
        "id": 94747,
        "reason": "Fico score is very low",
        "created_at": "2019-05-02T07:57:59.705578",
        "decline_code": "fico_too_low",
        "leaf_node_id": 5,
        "decision_type": "credit",
        "triggers_noaa": true,
        "general_description": "FICO score is too low"
    }
]

[
    {
        "id": 94772,
        "reason": "Lead Fico Threshold is not Greater Than Or Equal To 500",
        "created_at": "2019-05-02T07:58:05.988900",
        "decline_code": "fico_too_low",
        "leaf_node_id": 7,
        "decision_type": "credit",
        "triggers_noaa": true,
        "general_description": "FICO score is too low"
    },
    {
        "id": 94771,
        "reason": "Fico score is very low",
        "created_at": "2019-05-02T07:58:05.964931",
        "decline_code": "fico_too_low",
        "leaf_node_id": 5,
        "decision_type": "credit",
        "triggers_noaa": true,
        "general_description": "FICO score is too low"
    }
]

对于id=34257，这是JSONB格式的“dec_Reasions”值：

[
    {
        "id": 94748,
        "reason": "Lead Fico Threshold is not Greater Than Or Equal To 500",
        "created_at": "2019-05-02T07:57:59.706448",
        "decline_code": "fico_too_low",
        "leaf_node_id": 7,
        "decision_type": "credit",
        "triggers_noaa": true,
        "general_description": "FICO score is too low"
    },
    {
        "id": 94747,
        "reason": "Fico score is very low",
        "created_at": "2019-05-02T07:57:59.705578",
        "decline_code": "fico_too_low",
        "leaf_node_id": 5,
        "decision_type": "credit",
        "triggers_noaa": true,
        "general_description": "FICO score is too low"
    }
]

[
    {
        "id": 94772,
        "reason": "Lead Fico Threshold is not Greater Than Or Equal To 500",
        "created_at": "2019-05-02T07:58:05.988900",
        "decline_code": "fico_too_low",
        "leaf_node_id": 7,
        "decision_type": "credit",
        "triggers_noaa": true,
        "general_description": "FICO score is too low"
    },
    {
        "id": 94771,
        "reason": "Fico score is very low",
        "created_at": "2019-05-02T07:58:05.964931",
        "decline_code": "fico_too_low",
        "leaf_node_id": 5,
        "decision_type": "credit",
        "triggers_noaa": true,
        "general_description": "FICO score is too low"
    }
]

在每个'dec_reasons'值中，都有'reasons'键的多个实例。如何在每个“dec_reasons”值中查询与第一个“reason”实例配对的值

如果我查询了'reason'键的第一个实例，我希望看到：

'Lead Fico Threshold is not Greater Than Or Equal To 500'

'Fico score is very low'

如果我查询'reason'键的第二个实例，我希望看到：

'Lead Fico Threshold is not Greater Than Or Equal To 500'

'Fico score is very low'

---

要在jsonb结构中进行查询，您可以使用

->

向下搜索。这将获取第二个条目中的

键的值

# select '[{"key": 10},{"key": 20},{"key": 30}]'::jsonb->1->'key';
 ?column? 
----------
 20
(1 row)

或者您可以使用
#>
直接查询路径

# select '[{"key": 10},{"key": "20"},{"key": 30}]'::jsonb#>'{1,"key"}';
 ?column? 
----------
 "20"
(1 row)

请参阅博士后文档