Two revisions later, SQL-92 saw the first sweeping changes to the language. The actual spec itself grew exponentially in this release, though new features only accounted for double the size of the standard. The primary goal for SQL-92 was to be much more specific about how things should be done, thus lowering the amount of divergence between the various relational database platforms in the market.
SQL has continued to grow over the years, gaining recursive queries in 1999, adding XML support in 2003, and taking in XQuery support in 2006. Which brings us to today, when the SQL 2011 standard rules the roost.
SQL:2011, as it is called, was primarily about temporal support. This version of the standard brought in more handlers for doing work related to time series inside databases. This means most SQL databases (such as PostgreSQL, Oracle and DB2) can now treat time as a top-level function across SQL, and there are new temporal predicates, such as overlaps, equals and precedes. This means time-series database work should be easier to sync up across different vendors.
Oracle, for example, supports SQL:2011 in 12c, but versions 10g and 11g use Oracle’s Flashback queries to ask time-based questions to their databases. IBM, on the other hand, calls its temporal features Time Travel Queries.
This, perhaps, all points to the future for the SQL standard. As SQL has evolved over the past 40 years, it’s consistently taken on the common data challenges of the day with an approach that comes close to making everyone happy.
The Big Data connection
One place where the future of SQL is evident is in the world of Big Data. When Apache Hadoop burst onto the scene in 2010, there were no SQL tools in sight. But as of 2014, SQL on Hadoop has become essential.
A major reason for the continuing popularity of SQL, said Vicky Harp, corporate strategist at Idera, is that open source has democratized the language, opening it to more than simply enterprise users.
“For a long time, [SQL] was something people saw as [for the] big enterprise, but now we have other open-source alternatives, so people don’t have to make the big investment that they did before. You have a lot more developers who know SQL now,” she said.