Count(1) vs Count(*) with group by

[hend.amin]

Hello,

I had a query  select x, count(1) from myTable group by x;

The count was wrong.

However when i used  select x, count(*) from myTable group by x; the results were correct.

What does count(1) vs count(*) do ?

[shawkins]

> What does count(1) vs count(*) do ?

Normally you would expect them to be the same.

To determine why they are different, we'll need a fuller picture of what is happening here. 

- a query plan

- what source(s) are being targeted

- the Teiid version