DQL操作(SELECT)
- SELECT语法
 - SELECT语序
 - 子查询(SUBQUERY)
 - 交集(INTERSECT)、并集(UNION)和补集(EXCEPT)
 - JOIN
 - SEMI JOIN(半连接)
 - MAPJOIN HINT
 - SUBQUERY_MAPJOIN HINT
 - DISTRIBUTED MAPJOIN
 - SKEWJOIN HINT
 - Split Size Hint
 - 动态过滤器(Dynamic Filter)
 - LATERAL VIEW
 - GROUPING SETS
 - SELECT TRANSFORM
 - WINDOW关键字
 - TABLESAMPLE采样
 - QUALIFY
 - PIVOT、UNPIVOT
 - Time travel查询与增量查询
 - COMMON TABLE EXPRESSION(CTE)