Project Scenario:
When the large-screen statistics are displayed, the number of clicks per day is calculated according to the date
Problem description:
Reason analysis:
Mysql > execute SQL statements in order:
From — > WHERE — > group by — > having — > select — > order by
As you can see, select is executed after group by and having, so what’s the problem? Group by doesn’t have an alias yet, because the alias is generated in select, and select is after group by, so that’s an error
On the contrary
The hive SQL is executed in the following order:
From — > WHERE — > select — > group by — > having — > order by
Solution:
Do not use an alias for group by