我想使用average()与case,然而我的命令下面似乎给了我一个错误,但我不知道为什么
SELECT
avg(case when price between 0 AND 9 then price end),
avg(case when price between 10 AND 19 then price end),
avg(case when price between 20 AND 29 then price end),
avg(case when price between 30 AND 39 then price end),
avg(case when price between 40 AND 49 then price end)
FROM products;
数据库看起来像这样:
ProductID ProductName Price
1 Chais 18
2 Chang 19
3 Aniseed Syrup 33
8 Northwoods Cranberry Sauce 40
9 Mishi Kobe Niku 97
也许你需要这样的东西:
select avg (price) from products where price > 30