sql - MySQL column manipulation nonsense -

for sake of example, have column of ints looks this:

column1   1   2   3    4    5 

i have following code:

select column1+1 table 

which returns you'd expect:

column1   2   3   4    5    6 

on other hand if do:

select column1+avg(column1) table 

i complete nonsense, single row. sincerely apologize if basic but, have no idea what's going on here. i've tried using cast on every possible combination of "colum1+avg(colum1)" still returns nonsense.

when have avg() in select, telling sql have aggregation query. without group by, 1 row.

you intend this:

select column1 + (select avg(column1) table) table;