PostgreSQL

Question

很抱歉这里的格式。文本太多，无法创建可读性 table，请耐心等待。

我有一个叫 'declines' 的 table。它有两列：'id' 和 'dec_reasons'.

对于 id = 34254，这是 JSONB 格式的 'dec_reasons' 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"
    }
]

对于 id = 34257，这是 JSONB 格式的 'dec_reasons' 值：

[
    {
        "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，'reason' 键有多个实例。如何在每个 'dec_reasons' 值中查询与 'reason' 的第一个实例配对的值？

如果我查询 'reason' 键的第一个实例，我希望看到：

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

如果我查询 'reason' 键的第二个实例，我希望看到：

'Fico score is very low'

Answer 1

要在 jsonb 结构中查询，您可以使用 -> 向下钻取。这会在第二个条目中获取 key 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 Postgres 文档中的 json and jsonb Operators。

PostgreSQL - 查询 JSONB 数据中键的第 N 个实例的值

PostgreSQL - query the value for Nth instance of key in JSONB data

jsonb