A ground-up SQL implementation with window functions, PL/pgSQL-style stored procedures, a rich function library, and a cost-based optimizer that understands Delta Lake file statistics.
Common analytical functions across numeric, string, temporal, and aggregate categories
Arithmetic, exponential, logarithmic, trigonometric, and hyperbolic functions. Decimal arithmetic with exact precision. Rounding, bucketing, and number-theory helpers.
Substring, pattern matching, regex, case conversion, padding, concatenation, encoding, hashing (md5, sha256, sha512), and array-to-string operations.
Timestamp arithmetic, date truncation, component extraction, timezone conversion, interval operations, and calendar functions (day-of-week, quarter, week-of-year).
Standard aggregates plus statistical functions: variance, standard deviation, correlation, covariance, linear regression coefficients, percentiles, and mode.
Full frame specification including ROWS, RANGE, and GROUPS modes with exclusion clauses
ROW_NUMBER, RANK, DENSE_RANK, NTILE, PERCENT_RANK, CUME_DIST. Partition and order clauses supported on all ranking functions.
FIRST_VALUE, LAST_VALUE, NTH_VALUE, LAG (previous row), and LEAD (next row) with default-value support for boundary rows.
ROWS BETWEEN (physical row offsets), RANGE BETWEEN (logical value ranges, including interval-based ranges for time series), and GROUPS BETWEEN (peer group frames).
EXCLUDE NO OTHERS, EXCLUDE CURRENT ROW, EXCLUDE GROUP, and EXCLUDE TIES for precise control over which rows count in each frame.
SELECT
customer_id,
order_date,
amount,
SUM(amount) OVER (
PARTITION BY customer_id
ORDER BY order_date
ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
) AS running_total,
AVG(amount) OVER (
PARTITION BY customer_id
ORDER BY order_date
RANGE BETWEEN INTERVAL '7 days' PRECEDING AND CURRENT ROW
) AS moving_avg_7d
FROM orders;Procedural logic runs inside the engine, alongside your SQL, with full transaction semantics
Scalar variables, record types, %TYPE column references, %ROWTYPE table row types, array variables, and CONSTANT declarations with default values.
IF/THEN/ELSIF/ELSE, CASE WHEN, LOOP/EXIT/CONTINUE, WHILE, FOR over integer ranges and query result sets, and FOREACH over arrays.
EXCEPTION WHEN blocks with predefined exception types, RAISE EXCEPTION/NOTICE/WARNING, SQLSTATE error codes, and SQLERRM error messages.
Implicit cursor FOR loops, explicit cursor declaration, parameterized cursors, OPEN/FETCH/CLOSE lifecycle, and REFCURSOR return type for set-returning functions.
CREATE OR REPLACE FUNCTION process_monthly_billing(
p_month DATE,
p_discount_threshold DECIMAL DEFAULT 1000.00
) RETURNS TABLE(
customer_id INT,
total_amount DECIMAL,
discount_applied DECIMAL,
final_amount DECIMAL
) AS $$
DECLARE
v_customer RECORD;
v_total DECIMAL;
v_discount DECIMAL;
v_processed INT := 0;
BEGIN
FOR v_customer IN
SELECT id, tier FROM customers WHERE status = 'active'
LOOP
SELECT COALESCE(SUM(amount), 0) INTO v_total
FROM orders
WHERE customer_id = v_customer.id
AND date_trunc('month', order_date) = date_trunc('month', p_month);
v_discount := CASE
WHEN v_customer.tier = 'platinum' AND v_total > p_discount_threshold THEN v_total * 0.15
WHEN v_customer.tier = 'gold' AND v_total > p_discount_threshold THEN v_total * 0.10
WHEN v_total > p_discount_threshold * 2 THEN v_total * 0.05
ELSE 0
END;
customer_id := v_customer.id;
total_amount := v_total;
discount_applied := v_discount;
final_amount := v_total - v_discount;
RETURN NEXT;
v_processed := v_processed + 1;
END LOOP;
RAISE NOTICE 'Processed % customers for month %', v_processed, p_month;
EXCEPTION
WHEN OTHERS THEN
RAISE EXCEPTION 'Billing error: % - %', SQLSTATE, SQLERRM;
END;
$$ LANGUAGE plpgsql;Window functions, stored procedures, Cypher graph queries, and a cost-based optimizer that reads Delta statistics.