BETWEEN للنطاقات

BETWEEN شامل

SELECT * FROM orders WHERE total BETWEEN 100 AND 500;
-- equivalent to:
SELECT * FROM orders WHERE total >= 100 AND total <= 500;

نطاقات التواريخ

SELECT * FROM orders
WHERE created_at BETWEEN '2024-01-01' AND '2024-12-31';

مشكلة الحدّ الشامل

-- WRONG — misses orders later on Dec 31:
WHERE created_at BETWEEN '2024-12-01' AND '2024-12-31';

-- RIGHT — half-open interval:
WHERE created_at >= '2024-12-01'
  AND created_at <  '2025-01-01';

يُفضّل استخدام الفواصل الزمنية نصف المفتوحة

WHERE created_at >= date_trunc('month', NOW())
  AND created_at <  date_trunc('month', NOW()) + INTERVAL '1 month';

NOT BETWEEN

SELECT * FROM products WHERE price NOT BETWEEN 10 AND 20;
-- equivalent to: price < 10 OR price > 20

استعلامات النطاق والفهارس

CREATE INDEX orders_user_total_idx ON orders (user_id, total);

-- Efficient: equality on user_id, range on total
SELECT * FROM orders
WHERE user_id = 42 AND total BETWEEN 100 AND 500;

السلاسل النصية وBETWEEN

SELECT * FROM users WHERE last_name BETWEEN 'A' AND 'C';
-- Includes 'Adams' and 'Bond', excludes 'C' itself only if 'C' < 'Ca...'

أنواع النطاق (PostgreSQL)

SELECT int4range(10, 20) @> 15;       -- true  (15 in [10,20))
SELECT tsrange('2024-01-01', '2025-01-01') @> NOW()::TIMESTAMP;

التحقق من النطاقات باستخدام CHECK

CREATE TABLE bookings (
  id BIGSERIAL PRIMARY KEY,
  start_at TIMESTAMPTZ NOT NULL,
  end_at   TIMESTAMPTZ NOT NULL,
  CHECK (start_at < end_at)
);

تجميع القيم الرقمية في نطاقات

SELECT id, total,
  CASE
    WHEN total BETWEEN 0 AND 99    THEN 'small'
    WHEN total BETWEEN 100 AND 999 THEN 'medium'
    ELSE 'large'
  END AS bucket
FROM orders;

BETWEEN SYMMETRIC

SELECT 5 BETWEEN SYMMETRIC 10 AND 1;   -- TRUE

مراجعة

تحقق سريع