mysql 正负数计算

-- 示例：使用 DECIMAL 类型进行精确计算
CREATE TABLE financial_transactions (
    id INT PRIMARY KEY,
    amount DECIMAL(10, 2)
);

INSERT INTO financial_transactions (id, amount) VALUES (1, 100.50), (2, -50.25);

SELECT SUM(amount) AS total_amount FROM financial_transactions;

-- 示例：添加索引优化查询
CREATE INDEX idx_amount ON financial_transactions(amount);

SELECT SUM(amount) AS total_amount FROM financial_transactions WHERE amount > 0;

-- 示例：使用 BIGINT 类型处理大数值
CREATE TABLE large_numbers (
    id INT PRIMARY KEY,
    amount BIGINT
);

INSERT INTO large_numbers (id, amount) VALUES (1, 9223372036854775807), (2, -9223372036854775808);

SELECT SUM(amount) AS total_amount FROM large_numbers;