将值与平均值进行比较 SQL

Question

I have a database with some persones stored in it, this persons have a residuallLave (holiday days they haven´t needed). Now I want to get the average value of this residualLeave and compare which persons have more than the average. But I get only one person back and this can't be true because there are more persons with a more residualLeave.

Code:

Output:

Answer 1

Your query won't work because you compare "normal" columns with aggregated ones without grouping. It is way simpler like this:

select *
from tpersons
where residualLeave > (select avg(residualLeave) from tpersons)

Answer 2

Just for fun, here is a MySQL 8+ version using analytic functions:

SELECT persid, firstname, lastname, residualleave
FROM (SELECT *, AVG(residualleave) OVER () AS avgresidualleave FROM tpersons) t
WHERE residualleave > avgresidualleave;