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)
TAJO-232: Rename join operators and add other join operators to PhysicalPlanner. (hyunsik)