Stop making this so fucking complicated.
This has nothing to do with SQL, or IT staff or techies or the internal workings of an email system.
Under the conditions under which the Office of the Secretary of State works there is precisely one acceptable and legal way to follow the law under the Federal Records Act: print and store the emails for transfer to the National Archives. She can print them or her subordinate can print them but printed they must be.
Some of the reasons for this are because of decisions made by past Secretaries of State and continued under Secretary Clinton's watch. This, by the way, will change for all federal agencies on January 1, 2017.
Your complex example is specifically prohibited for recordkeeping because of how the Office of the Secretary is managed - through no fault of Secretary Clinton. What is at fault is her failing to assure that her office executed the statutory requirements incumbent on all members of the cabinet.
You only want to fault her if it was a good statute. Thus far, there's no evidence that the rest of the federal government has any issue with following the law as it relates to record keeping so why should she be exempt?
You keep coming back to using your knowledge of how email systems work and how YOU would perform a search for records. You incorrectly presume that the email system is a valid recordkeeping system for federal records; it is not. It isn't for many reasons spelled out in the National Archives statutes and regulations that implement the Federal Record Keeping statute.
If the email system was a valid recordkeeping system, and if it was a single monolithic system, and if it was capable of never losing data and if it was easily searchable by subject then, just maybe, the National Archives would accept your method of keeping records. Since it isn't, they've chosen a method that differs from your theoretical approach on how it should work. I'm sorry to be the bearer of bad news.
The Federal Record Keeping statute was put in place so that historical records could be preserved until the end of the Republic, or, at least, until they no longer have significance. It was put in place long before emails or electronic recordkeeping systems existed. Email, through the end of this year anyway, is force-fitted into the existing structure.
She and her staff didn't follow the law. That's not my opinion but the opinion of the Inspector General of the Department of State. Go complain to the IG's office if you want an easier SQL implementation put in place.