SQL CASE comparing Text Datarow with Int Datarow - mysql

Question

In my table, there is the Datarow Comment, which is stored as Text Datatype.
And I have the Datarow idPersonalstamm which is stored as an int.
My Problem is, sometimes it happens that the Data from Personalstamm gets copied in comment.
So I made a case statement which should cast both to varchar and then compare them and if comment equals personalstamm it should set comment as Null if not it should give that comment.
But it always goes to the else statement. What's my fault or how can I achieve my goal in a different way?
The whole thing is part of an Powershell Script which pulls this query once a week from a visitor terminal.
> My output looks like this
> Nr. id. Comment.
>1---2----2
> 2---3---some text
> 3---4---
> it should look like this
>Nr. id. Comment.
>1---2---
>2---3---some text
>3---4---
<pre><code>SELECT ROW_NUMBER() OVER(ORDER BY vb.Arrival ASC) AS Nr,
p.idPersonalstamm,
CASE vr.rating
WHEN 3 THEN 'Sehr Gut'
WHEN 2 THEN 'Gut'
WHEN 1 THEN 'Nicht so Gut'
ELSE 'Sonstiges'
END AS Bewertung,
<b>Case
WHEN CAST(vr.Comment as varchar (20)) = CAST(p.idPersonalstamm as varchar (20)) Then null
ELSE vr.Comment
END as Comment,</b>
vb.Arrival,
vb.Departure,
p.Name,
p.FirstName,
p.Company,
p.Stadt
From Personalstamm p
left join (
select vr.*,
row_number() over (partition by idPersonalstamm order by idPersonalstamm) as seqnum
from VisitRating vr
) vr on p.idPersonalstamm = vr.idPersonalstamm
left join (
select vb.*,
row_number() over (partition by idVisitor order by idVisitor) as seqnum
from VisitorBooking vb
) vb on p.idPersonalstamm = vb.idVisitor and vb.seqnum = vr.seqnum
where p.idPersonalstamm is not null</code></pre>

Answer 1

Could you try:
Case
WHEN LTRIM(CAST(vr.Comment as varchar (20))) = CAST(p.idPersonalstamm as varchar (20)) Then null
ELSE vr.Comment
END as Comment
or:
Case WHEN CAST(p.idPersonalstamm as varchar (20)) like '%' + CAST(vr.Comment as varchar (20)) + '%' Then null
ELSE vr.Comment
END as Comment