tps/srce.pgsql

/*
SELECT
jsonb_pretty(
$$
{
    "name": "GOOGDM",
    "type": "json_csv",
    "schema": {
        "rows": [
            {
                "elements": [
                    {
                        "status": "text",
                        "distance": {
                            "text": "text",
                            "value": "numeric"
                        },
                        "duration": {
                            "text": "text",
                            "value": "value"
                       }
                    }
                ]
            }
        ],
        "status": "text",
        "origin_addresses": [
            "text"
        ],
        "destination_addresses": [
            "text"
        ]
    },
    "unique_constraint": {
        "type": "key",
        "fields": [
            "{origin_adresses,0}",
            "{destination_adresses,0}"
        ]
    }
}
$$::jsonb
)
*/

DO $$

declare _t text;

begin
	
	SELECT
        string_agg(quote_ident(prs.key)||' '||prs.type,',')
    INTO
    	_t
    FROM 
        TPS.srce
        --unwrap the schema definition array
        LEFT JOIN LATERAL jsonb_populate_recordset(null::tps.srce_defn_schema, defn->'schema') prs ON TRUE
    GROUP BY
        srce;
        
    raise notice '%', _t;
    _t := format('CREATE TEMP TABLE csv_i (%s)', _t);
    raise notice '%', _t;
    
    DROP TABLE IF EXISTS csv_i;
    
    EXECUTE _t;

end
$$;

SELECT * FROM csv_i;