Querying with Primer (Intermediate)

In the previous cookbook recipe, you were able to use Primer to query the blockchain for exact matches and with the dot notation. In this guide, we will use Primer’s comparison operators and combine query criteria to make compound queries.

Comparison operators

The operators include: >, <, >=, <=, ===, and !==

Operator Primer Description
> $gt Greater than
< $lt Less than
>= $ge Greater than or equal
<= $le Less than or equal
=== $eq Equal to
!== $ne Not equal to

Let’s use a real-world example from the transaction endpoint. We have set no-logs to true to omit logs for simplicity.

// https://api.covalenthq.com/v1/1/address/0x5a6d3b6bf795a3160dc7c139dee9f60ce0f00cae/transactions_v2/?no-logs=true&page-number=0&page-size=5&key=...
{
  "data": {
    "address": "0x5a6d3b6bf795a3160dc7c139dee9f60ce0f00cae",
    "updated_at": "2021-03-15T04:52:25.163178447Z",
    "next_update_at": "2021-03-15T04:57:25.163179170Z",
    "quote_currency": "USD",
    "chain_id": 1,
    "items": [
      {
        "block_signed_at": "2021-02-20T17:47:24Z",
        "tx_hash": "0xf6d6298acb1df20ce05d272c270614cc7ff9d4a4dc699e9ac7110dbb36db0130",
        "tx_offset": 121,
        "successful": true,
        "from_address": "0x5a6d3b6bf795a3160dc7c139dee9f60ce0f00cae",
        "from_address_label": null,
        "to_address": "0x090d4613473dee047c3f2706764f49e0821d256e",
        "to_address_label": "Uniswap: Token Distributor",
        "value": "0",
        "value_quote": 0.0,
        "gas_offered": 90071,
        "gas_spent": 81883,
        "gas_price": 182000000000,
        "gas_quote": 28.776617,
        "gas_quote_rate": 1930.9658
      },
      {
        "block_signed_at": "2021-01-02T07:32:21Z",
        "tx_hash": "0x5541d233d378cb47916dbbe89720fe8f38acad1345aa8d320b1bcda1cfe88c4e",
        "tx_offset": 153,
        "successful": true,
        "from_address": "0x5a6d3b6bf795a3160dc7c139dee9f60ce0f00cae",
        "from_address_label": null,
        "to_address": "0xd9e1ce17f2641f24ae83637ab66a2cca9c378b9f",
        "to_address_label": null,
        "value": "33583608856374710",
        "value_quote": 26.144056,
        "gas_offered": 227697,
        "gas_spent": 193660,
        "gas_price": 40700000000,
        "gas_quote": 6.1359234,
        "gas_quote_rate": 778.4767
      },
      {
        "block_signed_at": "2021-01-02T05:48:25Z",
        "tx_hash": "0xfa442f76d8e5dd13ac49e4dd3c5272286c5cce9e094b5e0a93d2d2548d41537e",
        "tx_offset": 157,
        "successful": true,
        "from_address": "0x5a6d3b6bf795a3160dc7c139dee9f60ce0f00cae",
        "from_address_label": null,
        "to_address": "0x06da0fd433c1a5d7a4faa01111c044910a184553",
        "to_address_label": null,
        "value": "0",
        "value_quote": 0.0,
        "gas_offered": 66531,
        "gas_spent": 44354,
        "gas_price": 39000000000,
        "gas_quote": 1.3466136,
        "gas_quote_rate": 778.4767
      },
      {
        "block_signed_at": "2021-01-02T05:48:25Z",
        "tx_hash": "0xe8e564a57b2a60eb7fefe1626c5ae1617b510c3e7bf4932a76b9e9fb4e360573",
        "tx_offset": 156,
        "successful": false,
        "from_address": "0x5a6d3b6bf795a3160dc7c139dee9f60ce0f00cae",
        "from_address_label": null,
        "to_address": "0xd9e1ce17f2641f24ae83637ab66a2cca9c378b9f",
        "to_address_label": null,
        "value": "40000000000000000",
        "value_quote": 31.139067,
        "gas_offered": 241100,
        "gas_spent": 23166,
        "gas_price": 35000000000,
        "gas_quote": 0.6311967,
        "gas_quote_rate": 778.4767
      },
      {
        "block_signed_at": "2021-01-02T05:18:34Z",
        "tx_hash": "0x524d4131b0ceb2710b9d937daa0e43481b8c1950045caede2f4bb9e8863193b9",
        "tx_offset": 134,
        "successful": true,
        "from_address": "0x5a6d3b6bf795a3160dc7c139dee9f60ce0f00cae",
        "from_address_label": null,
        "to_address": "0x6b3595068778dd592e39a122f4f5a5cf09c90fe2",
        "to_address_label": null,
        "value": "0",
        "value_quote": 0.0,
        "gas_offered": 48847,
        "gas_spent": 44407,
        "gas_price": 36300000000,
        "gas_quote": 1.2548842,
        "gas_quote_rate": 778.4767
      }
    ],
    "pagination": {
      "has_more": true,
      "page_number": 0,
      "page_size": 5,
      "total_count": null
    }
  },
  "error": false,
  "error_message": null,
  "error_code": null
}

Select records using the less-than operator.

The following example retrieves all records from the transaction endpoint where the gas_spent field is less than 50000:

---
header: The less-than operator
---
{
    "gas_spent": {
      "$lt": 50000
    }      
}

Logical operators

Select records using logical operators

The following example retrieves all records from the transaction endpoint where the gas_spent field is between 50000 and 100000:

---
header: The $and logical operator operator
---
{
    "gas_spent": {
      "$and": [
        {
          "gas_spent": {
            "$gt": 50000
          }
        },
        {
          "gas_spent": {
            "$le": 100000
          }
        }
      ]
    }      
}

Datetime values

Select records using comparison operators on datetimes

The comparison operators also work with date time values. Here’s an example of selecting records that belong to a block after a certain date:

---
header: Comparisons operators on datetimes
---
{
    "block_signed_at": {
      "$gt": "2021-01-02"
    }      
}

Access array elements

Dot notation to access an element at a particular index on an array

You can use the dot notation to access an array by index. For example, you can access the second parameter of a decoded event:

---
header: Access the second element of the params array and only return result if value is 120000
---
{
    "decoded.params.1.value": 120000      
}
Last modified: January 25, 2022: Klatyn Banner updated. (#166) (4da460d)