PostgreSQLSUMCLAUSE返回错误的值

重新检查查询，确保符合预期的结果。

示例代码：

CREATE TABLE sales ( id SERIAL PRIMARY KEY, product TEXT, amount INT );

INSERT INTO sales (product, amount) VALUES ('A', 10), ('B', 20), ('C', 30);

-- 正确结果应该是60 SELECT SUM(amount) FROM sales WHERE product <> 'C';

-- 错误结果返回了90 SELECT SUM(amount) FROM sales WHERE product = 'C';

-- 根据预期结果查询 SELECT SUM(amount) FROM sales WHERE product <> 'C';

-- 重新检查数据 SELECT * FROM sales;