小编lra*_*rai的帖子

我有一个返回所需输出的查询。

SELECT 
    shop,
    JSON_AGG(item_history.* ORDER BY created_date DESC) as data
FROM item_history
GROUP BY
    shop;

结果：

[
  {
    "shop": "shop1",
    "data": [
      {
        "id": 226,
        "price": "0",
        "shop": "shop1.com",
        "country": "UK",
        "item": "item1",
        "created_date": "2021-06-07T08:48:42.338201",
      },
      {
        "id": 224,
        "price": "0",
        "shop": "shop1.com",
        "country": "UK",
        "item": "item 1",
        "created_date": "2021-06-07T07:53:25.030621",
      },
      ...
  },
  {
    "shop": "shop2",
    "data": [
      {
        "id": 225,
        "price": "0",
        "shop": "shop2.com",
        "country": "DE",
        "item": "Item 2",
        "created_date": "2021-06-07T08:48:36.443849",
      },
      ...
]

这正是我想要的输出，但问题是它获取data数组下的所有项目，最好限制该数组。我尝试添加LIMIT

SELECT …