Display only result > 2 - sql

Question

I face a problem with the result on my script.
My formula for MARGIN is ((plnamt-(ibhexc/ibhand))/plnamt)*100.
I want to display only result > 2. How to do this? Please help.
This my script:
select
a.plnitm,a.plnstr,max(a.plncdt),max(a.plnndt),max(a.plnamt),max(a.plnevt),b.idept,c.ibhand,c.ibhexc,
decimal((c.ibhexc/c.ibhand),12,4) as AVG_COST,
decimal(((((max(a.plnamt)-(c.ibhexc/c.ibhand))/(max(a.plnamt))))*100),12,4) as MARGIN
from prcpln a
inner join invmst b on a.plnitm = b.inumbr
inner join invbal c on a.plnitm = c.inumbr and a.plnstr = c.istore and c.ibhand <> 0
where a.plnstr = ''14006''
group by a.plnitm,a.plnstr,b.idept,c.ibhand,c.ibhexc
order by a.plnitm

Answer 1

Simplistically, for situations like this, you can take your query and put it inside a cte:
WITH q AS (
select
a.plnitm,a.plnstr,max(a.plncdt),max(a.plnndt),max(a.plnamt),max(a.plnevt),b.idept,c.ibhand,c.ibhexc,
decimal((c.ibhexc/c.ibhand),12,4) as AVG_COST,
decimal(((((max(a.plnamt)-(c.ibhexc/c.ibhand))/(max(a.plnamt))))*100),12,4) as MARGIN
from prcpln a
inner join invmst b on a.plnitm = b.inumbr
inner join invbal c on a.plnitm = c.inumbr and a.plnstr = c.istore and c.ibhand <> 0
where a.plnstr = ''14006''
group by a.plnitm,a.plnstr,b.idept,c.ibhand,c.ibhexc
)
SELECT * FROM q WHERE margin > 2
ORDER BY q.plnitm
This is similar to the advice to use HAVING - a HAVING is a "where clause that is done after a GROUP BY"
A cte is a way of taking some calculated block of data and giving it an alias that can be used just like a table. I wanted to answer this way to point out to you that queries don't have to be formed purely from tables; tables are just blocks of data (with a name), and the output from a select is also "just a block of data" that can be given a name (by use of a cte or subquery) and then used just like a table is