reworked q12. added more precise query description and adapted SQL accordingly
reworked q12. added more precise query description and adapted SQL accordingly

XiaominZhang/Big-Data-Benchmark-for-Big-Bench,philjjoon/Big-Data-Benchmark-for-Big-Bench,intel-hadoop/Big-Data-Benchmark-for-Big-Bench,XiaominZhang/Big-Data-Benchmark-for-Big-Bench,intel-hadoop/Big-Data-Benchmark-for-Big-Bench,philjjoon/Big-Data-Benchmark-for-Big-Bench