CREATE TABLE solicitations
(
  id SERIAL PRIMARY KEY,
  name text
);

CREATE TABLE donations
(
  id SERIAL PRIMARY KEY,
  solicitation_id integer REFERENCES solicitations, -- can be null
  created_at timestamp without time zone NOT NULL DEFAULT (now() at time zone 'utc'),
  amount bigint NOT NULL DEFAULT 0
);


INSERT INTO solicitations (name) VALUES
  ('solicitation1'), ('solicitation2');

INSERT INTO donations (solicitation_id, amount) VALUES
  (null, 10), (1, 20), (2, 30);

SELECT
"created_at"
, COALESCE("no_solicitation", 0) AS "no_solicitation"
, COALESCE("1", 0) AS "1"
, COALESCE("2", 0) AS "2"
FROM crosstab(
  $source_sql$
    SELECT
      created_at::date as row_id
    , COALESCE(solicitation_id::text, 'no_solicitation') as category
    , SUM(amount) as value
    FROM donations
    GROUP BY row_id, category
    ORDER BY row_id, category
  $source_sql$
, $category_sql$
    SELECT 'no_solicitation' AS foo
    UNION ALL
    SELECT DISTINCT id::text AS foo FROM solicitations ORDER BY foo
  $category_sql$
) AS ct (
  "created_at" date
, "no_solicitation" bigint
, "1" bigint
, "2" bigint
)