AFAIK OpenQuery does not work with a variables as parameters, you need to create the string inside the function call, ie
set @SQL = 'SELECT * FROM TABLE'
select * from OpenQuery(ORACLE, @SQL) -> Fail
select * from OpenQuery(ORACLE, 'SELECT * FROM TABLE') -> Works
IOW, you need to build your complex string inside the function call
[UPDATE] Ah, I did not see you were using EXEC... then what I said does not apply, but I never tried either...
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