S02021

错误代码

S02021

报错信息

The HAVING clause after GROUP BY must be followed by a boolean expression. RefId:S02021

错误原因

在 group by 子句中，having 计算的结果必须是布尔表达式，若结果不是布尔表达式，则会出现该报错。如以下场景中，having 的结果不是一个布尔表达式，出现报错：

n = 10000
id = take(1..10, n)
value = take(1..10, n)
t = table(id, value)

a = 1.0
select max(value) from t group by id having a // throw exception
select max(value) from t group by id having value // throw exception
select max(value) from t group by id having max(value) != 0 // OK

解决办法

检查查询中的 having 条件，确保其计算结果是一个布尔表达式。