There is an equivalent to SQL for multidimensional databases (OLAP) called MDX. Alas, just like XML has DOM, OLAP would need a standard open API. The closest thing we ever got was JOLAP. However, I reported in 2005 that the Java OLAP Interface (JOLAP) was dead.
Note: Yes, I am aware of the irony that my previous post was DUAT: Do not use acronyms in titles.