I think he's wrong, but Paul White said it very clearly: the question is too basic... [for some]. I think this adds tremendous confusion and dissuades people from using this site. As a member of the community that feels passionately and differently on this specific issue, I've also voted to reopen your question.
All SQL questions should be welcome here. "Basic" is entirely too subjective, and as someone growing and coming here looking for expertise you're probably not the right one to make that distinction. Not all admins on DBA.SE even use SQL: some of them come from GIS backgrounds or use record-based systems (ex, PICK) that lack the SQL query language. Some people use xquery. What do these guys do when they have SQL questions, level up at StackOverflow first?
I've tried to address this in a substantive way and to change this policy on a few occasions. It's an uphill battle. The sad part is that we really need more users like yourself to come here and ask good questions and grow in this community, and sending you off to StackOverflow to ask DBA-esque questions inhibits both your growth and the communities growth in the near and long-term. It's an all around bad and dated policy.
I've down-voted the others answers. I feel strongly about this and ejecting newer less experienced database users back to StackOverflow is a shameful act.
Not to mention there are tons of users here who want to help you learn, myself included and it's not exactly like the site has an abundance of questions: Tex, GIS, WordPress, SharePoint, Drupal, SalesForce, and Magneto StackExchanges all get more questions/day than us. I'd take a bet that they employee fewer people and have less-advanced subject matter than we do too.