It (replit-code-v1-3b) is already quite good at explaining code:

Input:

    below is a SQL statement:

    SELECT
      CAST(DATE_TRUNC('week', "t1"."TIMESTAMP") AS DATE) AS "WEEK_START",
      COUNT(\*) AS "EVENT_COUNT"
    FROM "ANALYTICS"."POSTHOG"."POSTHOG_EVENTS" AS "t1"
    GROUP BY
      "WEEK_START"
    ORDER BY
      "WEEK_START"
    LIMIT 2000

    Explain this SQL. Respond in JSON format with the following keys: 
    TITLE, DESCRIPTION, TABLES
    JSON response:

output:

    {
        "title": "Weekly Events Count",
        "description": "Count of weekly events",
        "tables": [
            {
                "name": "POSTHOG_EVENTS",
                "columns": [
                    "WEEK_START",
                    "EVENT_COUNT"
                ]
            }
        ]
    }