https://cwiki.apache.org/confluence/display/Hive/LanguageManual+Select

查询语句语法：

SELECT [ALL | DISTINCT] select_expr, select_expr, ...

FROM table_reference

[WHERE where_condition]

[GROUP BY col_list]

[ORDER BY col_list]

[CLUSTER BY col_list

| [DISTRIBUTE BY col_list] [SORT BY col_list]

]

[LIMIT number]

6.1 基本查询（Select…From）

6.1.1 全表和特定列查询

0）数据准备

（0）原始数据

dept:

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20  RESEARCH    1800

30  SALES   1900