How to rewrite sql query after where condition with another query ?

Question

I work on sql server I need to rewrite statement after where statement so how to rewrite

I don't understand what is writing after where

so can you help me how to write it alternative

select top 1 *
FROM
dbo.GlobalPartNumberPortions Po WITH(NOLOCK)
INNER JOIN dbo.GlobalPartNumber GOl WITH(NOLOCK) ON GOl.GlobalPnId = Po.GlobalPnId AND Po.GroupId = 1
INNER JOIN Parts.Nop_PartsFamily pf WITH(NOLOCK) ON GOl.FamilyId = pf.PartFamilyID
INNER JOIN dbo.GlobalPartNumberPortions Po2 WITH(NOLOCK) ON GOl.GlobalPnId = Po2.GlobalPnId AND Po2.GroupId = 2
WHERE @PartNumber LIKE CONCAT(LTRIM(RTRIM(CASE WHEN Po.PortionKey=N'Blank' THEN ''
WHEN CHARINDEX('[', PO.PortionKey) >0 then replace(PO.PortionKey,N'[',N'[[')
ELSE Po.PortionKey END))
,LTRIM(RTRIM(CASE WHEN Po2.PortionKey=N'Blank' THEN ''
WHEN CHARINDEX('[', PO2.PortionKey) >0 then replace(PO2.PortionKey,N'[',N'[[')
ELSE Po2.PortionKey END))
, '%')

what i need it rewrite statement as below :

WHERE @PartNumber LIKE CONCAT(LTRIM(RTRIM(CASE WHEN Po.PortionKey=N'Blank' THEN ''
WHEN CHARINDEX('[', PO.PortionKey) >0 then replace(PO.PortionKey,N'[',N'[[')
ELSE Po.PortionKey END))
,LTRIM(RTRIM(CASE WHEN Po2.PortionKey=N'Blank' THEN ''
WHEN CHARINDEX('[', PO2.PortionKey) >0 then replace(PO2.PortionKey,N'[',N'[[')
ELSE Po2.PortionKey END))
, '%')

really i don't understand what after where condition so can you help me to understand what written after where

condition

or

rewrite it with another syntax or logic ?

this actually i need to rewrite it

WHERE @PartNumber LIKE CONCAT(LTRIM(RTRIM(CASE WHEN Po.PortionKey=N'Blank' THEN ''
WHEN CHARINDEX('[', PO.PortionKey) >0 then replace(PO.PortionKey,N'[',N'[[')
ELSE Po.PortionKey END))
,LTRIM(RTRIM(CASE WHEN Po2.PortionKey=N'Blank' THEN ''
WHEN CHARINDEX('[', PO2.PortionKey) >0 then replace(PO2.PortionKey,N'[',N'[[')
ELSE Po2.PortionKey END))
, '%')

portion key is RXQ6R8

@PartNumber is RXQ6R8M2WSA-1020S