ex_money_sql

CREATE OR REPLACE FUNCTION money_min_state_function(agg_state money_with_currency, money money_with_currency)
RETURNS money_with_currency
IMMUTABLE
STRICT
LANGUAGE plpgsql
AS $$
  DECLARE
    expected_currency varchar;
    aggregate numeric;
    min numeric;
  BEGIN
    IF currency_code(agg_state) IS NULL then
      expected_currency := currency_code(money);
      aggregate := 0;
    ELSE
      expected_currency := currency_code(agg_state);
      aggregate := amount(agg_state);
    END IF;

    IF currency_code(money) = expected_currency THEN
      IF amount(money) < aggregate THEN
        min := amount(money);
      ELSE
        min := aggregate;
      END IF;
      return row(expected_currency, min);
    ELSE
      RAISE EXCEPTION
        'Incompatible currency codes. Expected all currency codes to be %', expected_currency
        USING HINT = 'Please ensure all columns have the same currency code',
        ERRCODE = '22033';
    END IF;
  END;
$$;


CREATE OR REPLACE FUNCTION money_min_combine_function(agg_state1 money_with_currency, agg_state2 money_with_currency)
RETURNS money_with_currency
IMMUTABLE
STRICT
LANGUAGE plpgsql
AS $$
  DECLARE
    min numeric;
  BEGIN
    IF currency_code(agg_state1) = currency_code(agg_state2) THEN
      IF amount(agg_state1) < amount(agg_state2) THEN
        min := amount(agg_state1);
      ELSE
        min := amount(agg_state2);
      END IF;
      return row(currency_code(agg_state1), min);
    ELSE
      RAISE EXCEPTION
        'Incompatible currency codes. Expected all currency codes to be %', expected_currency
        USING HINT = 'Please ensure all columns have the same currency code',
        ERRCODE = '22033';
    END IF;
  END;
$$;


CREATE AGGREGATE min(money_with_currency)
(
  sfunc = money_min_state_function,
  stype = money_with_currency,
  combinefunc = money_min_combine_function,
  parallel = SAFE
);


CREATE OR REPLACE FUNCTION money_max_state_function(agg_state money_with_currency, money money_with_currency)
RETURNS money_with_currency
IMMUTABLE
STRICT
LANGUAGE plpgsql
AS $$
  DECLARE
    expected_currency varchar;
    aggregate numeric;
    max numeric;
  BEGIN
    IF currency_code(agg_state) IS NULL then
      expected_currency := currency_code(money);
      aggregate := 0;
    ELSE
      expected_currency := currency_code(agg_state);
      aggregate := amount(agg_state);
    END IF;

    IF currency_code(money) = expected_currency THEN
      IF amount(money) > aggregate THEN
        max := amount(money);
      ELSE
        max := aggregate;
      END IF;
      return row(expected_currency, max);
    ELSE
      RAISE EXCEPTION
        'Incompatible currency codes. Expected all currency codes to be %', expected_currency
        USING HINT = 'Please ensure all columns have the same currency code',
        ERRCODE = '22033';
    END IF;
  END;
$$;


CREATE OR REPLACE FUNCTION money_max_combine_function(agg_state1 money_with_currency, agg_state2 money_with_currency)
RETURNS money_with_currency
IMMUTABLE
STRICT
LANGUAGE plpgsql
AS $$
  DECLARE
    max numeric;
  BEGIN
    IF currency_code(agg_state1) = currency_code(agg_state2) THEN
      IF amount(agg_state1) > amount(agg_state2) THEN
        max := amount(agg_state1);
      ELSE
        max := amount(agg_state2);
      END IF;
      return row(currency_code(agg_state1), max);
    ELSE
      RAISE EXCEPTION
        'Incompatible currency codes. Expected all currency codes to be %', expected_currency
        USING HINT = 'Please ensure all columns have the same currency code',
        ERRCODE = '22033';
    END IF;
  END;
$$;


CREATE AGGREGATE max(money_with_currency)
(
  sfunc = money_max_state_function,
  stype = money_with_currency,
  combinefunc = money_max_combine_function,
  parallel = SAFE
);