Formalize AVG Typing Output

[johnedquinn]

Description

What is the output static type of:

• AVG(tinyint)
• AVG(smallint)
• AVG(int)
• AVG(bigint)
• AVG(numeric(p, s))
• AVG(decimal(p, s))
• AVG(real)
• AVG(double precision)
• AVG(dynamic)

And, a follow up: If the input at compile-time was dynamic, what is the output value's type of all of the above (excluding the last case)?

For now, from a discussion with @jpschorr, we've decided that for the exact numeric types, since AVG = SUM / COUNT and COUNT returns a BIGINT (which has a precision of 19), then for the integral types, the output of average will be DECIMAL(38, 19). We need to think about this more and formalize this.

DoD

• This needs to be clarified and implemented.