Oracle Corp. (ORCL) is reluctant to give up its MySQL database product to gain antitrust clearance in Europe for its tie-up with Sun Microsystems (JAVA), due to its rivalry with Microsoft (MSFT), according to a document seen by Dow Jones Newswires Wednesday.

Oracle's position is that in the market for small to medium sized business databases, the MySQL database product enables the company to compete against Microsoft, which is the market leader in that segment, according to a questionnaire sent out by the European Commission to the firm's clients and competitors that is being used to assess the validity of Oracle's argument, as well as a person familiar with the investigation.

Oracle's $7.4 billion acquisition of Sun depends on an all-clear from Brussels, but the deal was dealt a blow in early September when the European Commission launched an in-depth four-month inquiry citing MySQL as a possible problem area. U.S. authorities have already cleared the acquisitions without asking for any divestments.

Europe's top antitrust enforcer said that it had launched the in-depth probe due to concerns that the deal might stymie competition in the database market, where both companies have products. MySQL was seen as problematic because the commission was worried both Oracle and Sun had competing database products, triggering fears that it would have to be sold off for antitrust clearance.

The commission is now asking whether Oracle's argument that Sun's MySQL database directly competes against Microsoft's databases is valid.

The deadline for responses to the MySQL questionnaire is Oct 5. The commission has until Jan. 19 to rule on the takeover.

-By Peppi Kiviniemi, Dow Jones Newswires; +3227411483; peppi.kiviniemi@dowjones.com