Why the Max aggregate function need the limit condition

Dremio University
1

When i write a comparion operator use the Max aggregate function,like this:

select * from A where A.fieldX >= (select max(fieldX) from A)

but dremio response a errror:

  Dremio doesn't currently support non-scalar sub-queries used in an expression

And,when i add the limit condition,it is normal.

select * from A where A.fieldX >= (select max(fieldX) from A limit 1)

WHY???

2

@knocher That is a known behavior and you exactly found the right workaround, we have an engineering ticket in the backlog to address this but the workaround should be fine

3

This issue has been addressed as of Dremio 16.1. If you are seeing this in 16.1 or higher, please share your query profile, as this is not expected.