Converting JSON Data to Tabular in Snowflake — From SQL to SPL #32

#esprocspl #sql #snowflke #tabular

Problem Description & Analysis:

The Snowflake database has a multi-layered JSON string:

{
  "enterprise": "xx",
  "genericTrap": "1",
  "pduBerEncoded": "xxx",
  "pduRawBytes": "xxxx",
  "peerAddress": "xx",
  "peerPort": "xx",
  "securityName": "xxx",
  "specificTrap": "1",
  "sysUpTime": "xxxx",
  "variables": [
    {
      "oid": "column_a",
      "type": "octetString",
      "value": "vala"
    },
    {
      "oid": "column_b",
      "type": "integer",
      "value": "valb"
    }
  ]
}

Task: Now we need to find the first layer field specificTrap as the grouping field; Find the first layer array variables, and extract the oid and value of each member as details.

Code Comparisons:

SQL：

with table_a(col) as (
    select
        parse_json(
            '{
  "enterprise": "xx",
  "genericTrap": "1",
  "pduBerEncoded": "xxx",
  "pduRawBytes": "xxxx",
  "peerAddress": "xx",
  "peerPort": "xx",
  "securityName": "xxx",
  "specificTrap": "1",
  "sysUpTime": "xxxx",
  "variables": [
    {
      "oid": "column_a",
      "type": "octetString",
      "value": "vala"
    },
    {
      "oid": "column_b",
      "type": "integer",
      "value": "valb"
    }
  ]
}'
        ) as variant
)
select
    any_value(specifictrap) specifictrap,
    max(case oid when 'column_a' then oid_val else null end)  column_a,
    max(case oid when 'column_b' then oid_val else null end)  column_b

from
    (
        select
            f.seq seq,
            col:specificTrap::VARCHAR specifictrap,
            f.value:oid::VARCHAR oid,
            f.value:value::VARCHAR oid_val
        from
            table_a,
            lateral FLATTEN(input => table_a.col:variables::ARRAY) f
    ) t
group by
    seq;

SQL does not support multiple layers of data and requires indirect implementation through nested queries and grouping aggregation, making the code difficult to understand.

SPL: SPL supports multi-layer data and allows direct access to multi-layer structures in an object-oriented manner:

✅ Try.DEMO