TAJO-226: Can't use group by column alias. (hyunsik)
TAJO-148: Implement UPPER(text), LOWER(text) function. (hyunsik)
TAJO-147: Implement trim(text), ltrim(text), and rtrim(text) function. (hyunsik)
TAJO-179: Support MySQL CatalogStore. (jinho)
TAJO-179: Support MySQL CatalogStore. (removed useless code)
Merge branch 'master' of https://git-wip-us.apache.org/repos/asf/incubator-tajo into TAJO-35