Schema names hard coded into procedures

Hi All,

I have 4 ECC systems coming in via SLT to four target schemas. Lets call them schema A, B, C and D. I have the same table..lets say VBAK in all of them.

Now I have a stored procedure which takes an input parameter called schemaName

The procedure has logic like:

if schemaName  = 'A'

{

select from A.VBAK

}

elseif schemaName  = 'B'

{

select from B.VBAK

}

elseif schemaName  = 'C'

{

select from C.VBAK

}

elseif schemaName  = 'D'

{

select from D.VBAK

}

Now the problem is that A,B,C,D map to M,N,O,P in the Quality environment and W,X,Y,Z in the prod.

Hard coded values won't undergo schema mapping upon transport and mentioning a default schema doesn't help since I have multiple schemas.

Confused on what to do.. How do i make the schema names switch in the If condition and in the select statement?

Let me know your thoughts on this.

Thanks,

Shyam