SQL TOP 1 issue when no record is found - sql

Question

Hope you can help me with this SQL issue I am unable to solve:
I have a price list file with multiple entries per item number like this:
ItemNo
ValidFrom
ValidTo
Price
Now when I try to generate a list with prices valid today, I use the statement below to get a decent report. I only have a problem when no valid price was found, i.e. for TODAY there is no record. In this case the first TOP 1 subquery still returns a (random?) value and destroys my report.
I assume that TOP 1 will always return one value by definition, or is there a trick which can prevent this?
Really appreciate your help! (and please excuse the german terms in the query...)
SELECT
MITBAL.MBITNO as 'Artikel', MITMAS.MMITDS as 'Bezeichnung',
MITBAL.MBBUYE as 'Disponent', MITMAS.MMNEWE as 'Gewicht',
MITBAL.MBSUNO as 'Lieferant', MMITTY as 'Typ',
m9ucos as 'Std.-Kosten', idsunm as 'Lieferantenname',
iicucd as 'WSL', MBEOQT as 'EOQ',
(select count(*)
from RCE12_Staging.dbo.mpagrl
left outer join RCE12_Staging.dbo.mpagrh on aicono = ahcono
and aiagnb = ahagnb and aisuno = ahsuno
where aicono = 2
and aiobv1 = mbitno and aisagl = 20
and aisuno between '400000' and '599999' and aigrpi = 40
and aiuvdt >= CONVERT(char(8), GETDATE(), 112) and ahpast = '40') as 'Anz.Lief',
(select TOP 1 ajpupr
from RCE12_Staging.dbo.mpagrp
left outer join RCE12_Staging.dbo.mpagrh on ajcono = ahcono
and ajagnb = ahagnb and ajsuno = ahsuno
left outer join RCE12_Staging.dbo.mpagrl on ajcono = aicono
and ajagnb = aiagnb and ajsuno = aisuno
where ajcono = 2
and ajobv1 = mbitno and ajsuno = mbsuno
and ajmapr = 1 and ajgrpi = 40
and ajfvdt < CONVERT(char(8), GETDATE(), 112) and ahpast = '40'
and ahfvdt < CONVERT(char(8), GETDATE(), 112)
and ahuvdt >= CONVERT(char(8), GETDATE(), 112)
and aisagl = 20 and aigrpi = 40
and aifvdt < CONVERT(char(8), GETDATE(), 112)
and aiuvdt >= CONVERT(char(8), GETDATE(), 112)
order by ajfvdt desc) as 'EK-Preis',
(select TOP 1 ajfrqt
from RCE12_Staging.dbo.mpagrp
left outer join RCE12_Staging.dbo.mpagrh on ajcono = ahcono
and ajagnb = ahagnb and ajsuno = ahsuno
left outer join RCE12_Staging.dbo.mpagrl on ajcono = aicono
and ajagnb = aiagnb and ajsuno = aisuno
where ajcono = 2 and ajobv1 = mbitno
and ajsuno = mbsuno and ajmapr = 1 and ajgrpi = 40
and ajfvdt < CONVERT(char(8), GETDATE(), 112) and ahpast = '40'
and ahfvdt < CONVERT(char(8), GETDATE(), 112)
and ahuvdt >= CONVERT(char(8), GETDATE(), 112) and aisagl = 20
and aigrpi = 40
and aifvdt < CONVERT(char(8), GETDATE(), 112)
and aiuvdt >= CONVERT(char(8), GETDATE(), 112)
order by ajfvdt desc) as 'EK-Menge'
FROM
RCE12_Staging.dbo.MITBAL MITBAL
left outer join
RCE12_Staging.dbo.MITFAC MITFAC ON mbcono = m9cono and mbitno = m9itno and m9faci = 'DFP'
left outer join
RCE12_Staging.dbo.MITMAS MITMAS ON mbcono = mmcono and mbitno = mmitno
left outer join
RCE12_Staging.dbo.CIDMAS CIDMAS ON mbcono = idcono and mbsuno = idsuno
left outer join
RCE12_Staging.dbo.CIDVEN CIDVEN ON mbcono = iicono and mbsuno = iisuno
WHERE
MITBAL.MBCONO = 2
AND MITBAL.MBWHLO = '200' AND MBSTAT = '20' AND MBPUIT = '2'
and MBITNO like '479200222%'
ORDER BY MBITNO

Answer 1

The 'top 1' will return the first row from the dataset if the dataset you have requested is empty then top 1 will return an empty dataset with no rows and no 'Random data'.
You should probably check the number of rows returned if you need the data for later in the query or initialise a variable and use that.