SQL's responsibility is to describe the data extraction as operations of relational algebra, including projection, join, etc.

from PA 4 I think that openmp is a DSL that has the responsibility of spawning threads and assigning work to them, taking care of implementing atomic regions, and barriers.

For MapReduce, programmer's responsibility is to define the operations to be performed on data (the map and reduce functions), and the MapReduce system schedules these operations on a cluster of machines and takes care of problems including worker failure, data locality etc.

In SQL, the programmer's responsibility is to declare the data queries desired, and sometimes to declare them in a way or order that avoids unnecessary computation (e.g. if you will filter certain data, filter it before you do other computations, not after, so that you only compute what you need). The responsibility of SQL itself is to actually implement searches on data stored in specific formats (e.g. row store, column store), implement operations like join (e.g. hash join, sort join) or sort (e.g. external merge sort). SQL also optimizes your query as much as it can, e.g. reordering operations, etc.