Group By子句中的别名 - 无效标识符[duplicate]

Question

这个问题在这里已有答案：

• SQL - using alias in Group By 9个答案

我通过很多方式尝试了很多次，但我无法解决这个问题......

我正在执行Oracle SQL查询：

SELECT
    TRUNC(months_between(sysdate, DateofBirth) / 12) AS "age"
FROM players
group by age
HAVING COUNT 
    (TRUNC(months_between(sysdate, DateofBirth) / 12)) > 30;

第4行的错误：ORA-00904：“AGE”：标识符无效

有任何想法吗？

Answer 1

在Oracle和SQL Server中，不能在SELECT子句中定义的GROUP BY子句中使用术语，因为GROUP BY在SELECT子句之前执行。

https://stackoverflow.com/a/3841804/6358346

正确的方法：

SELECT TRUNC(months_between(sysdate, DateofBirth) / 12) AS "age"
FROM players
GROUP BY TRUNC(months_between(sysdate, DateofBirth) / 12)
HAVING COUNT(TRUNC(months_between(sysdate, DateofBirth) / 12)) > 30;

Answer 2

不要在您的组中添加别名：

SELECT
    TRUNC(months_between(sysdate, DateofBirth) / 12) AS "age"
FROM players
group by
    TRUNC(months_between(sysdate, DateofBirth) / 12)
HAVING
    COUNT(TRUNC(months_between(sysdate, DateofBirth) / 12)) > 30;