For an environment consisting of Oracle 11g/12c enterprise edition, MySQL 5.7 community edition, and MSSQL 2008/2012 stanard/enterprise edition, is there any major issue using DG4ODBC to query data from all 3 platforms?
Is there other free alternatives?
If the queried data is mostly contained in MySQL or MSSQL, will it be more efficient to query from MySQL or MSSQL?
If yes, any suggestion of how to do it in those platforms? I know MSSQL can use linked server but it is quite slow.