Question

我基本上想要做的是：计算属性的差异，然后获得最大差异的行。

所以，这就是我的尝试：

SELECT caller_aor, (end_time - start_time) as duration
    FROM cdrs
    GROUP BY caller_aor
    HAVING duration = (SELECT MAX(end_time - start_time) FROM cdrs);

HAVING子句中的持续时间给出了错误，但我无法弄清楚我必须在那里做什么。

非常感谢帮助。

Answer 1

您不希望GROUP BY和HAVING（仅在聚合列时使用它们。）

你想要一个简单的WHERE：

SELECT caller_aor, (end_time - start_time) as duration
FROM cdrs
WHERE (end_time - start_time) = (SELECT MAX(end_time - start_time) FROM cdrs);

Answer 2

尝试此查询

SELECT top 1 caller_aor, Max(end_time - start_time) as duration
FROM cdrs
GROUP BY caller_aor
Order by duration

Answer 3

另一种看待这种情况的方法是使用limit。

SELECT caller_aor, (end_time-start_time) AS duration
FROM cdrs
ORDER BY duration DESC
LIMIT 1

使用别名获取此SQL语句

3 个答案: