SQL查询帮助 - 由于Average_Fee而无法运行

Question

我无法运行此查询，我不知道该怎么做才能修复它？不会因为Average_Fee而运行。

SELECT LENGTH, AVG(RENTAL_FEE) AVERAGE_FEE
FROM MARINA_SLIP
WHERE AVERAGE_FEE < 3500
GROUP BY LENGTH
ORDER BY LENGTH DESC;

Answer 1

每当使用avg(rental_fee)列表中的函数时，您需要使用AS子句为SELECT分配别名。

您无法在同一块内引用别名。此外，汇总功能的where是使用having条款完成的 - 它已应用于group。

SELECT LENGTH, AVG(RENTAL_FEE) AS AVERAGE_FEE 
FROM MARINA_SLIP 
GROUP BY LENGTH 
HAVING AVG(RENTAL_FEE) < 3500
ORDER BY LENGTH DESC;

Answer 2

您需要对聚合值使用having子句

SELECT LENGTH, AVG(RENTAL_FEE) AVERAGE_FEE
FROM MARINA_SLIP
GROUP BY LENGTH
HAVING AVERAGE_FEE < 3500
ORDER BY LENGTH DESC;