I have the following SQL Statement in a SSIS Execute SQL Task:

        use [master];
        declare @DatabaseBackupPath varchar(250) = ?;
        
        backup database [DW]
        to  disk = @DatabaseBackupPath
        with copy_only
           , noformat
           , init
           , name = N'DW-Full Database Backup'
           , skip
           , norewind
           , nounload
           , compression
           , stats = 10;
        go

Variables are configured correctly and if value is e.g. set to ‘C:DEVDW.bak’, I get the error below when I run the task (i.e. backup path is being prefixed with C:Program FilesMicrosoft SQL ServerMSSQL16.MSSQLSERVERMSSQLDATABACKUP):

Error: Cannot open backup device ‘C:Program FilesMicrosoft SQL ServerMSSQL16.MSSQLSERVERMSSQLDATABACKUP’C:DEVDW.bak”. Operating system error 123(The filename, directory name, or volume label syntax is incorrect.).

Our workload requires database to be restored in the event of a failure in the process and the Backup Database task is not suitable for us as it adds a timestamp to the database backup name. Any help with above error would be much appreciated.

If I put the query in a variable and then reference this in the execute SQL Task, it works but just wondered if anyone has encountered above issue before or can explain why it may be happening.