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DDL之表操作

操作 DDL
2023-09-14 09:06:09 时间

Create Table

CREATE [TEMPORARY] [EXTERNAL] TABLE [IF NOT EXISTS] [db_name.]table_name    -- (Note: TEMPORARY available in Hive 0.14.0 and later)
  [(col_name data_type [column_constraint_specification] [COMMENT col_comment], ... [constraint_specification])]
  [COMMENT table_comment]
  [PARTITIONED BY (col_name data_type [COMMENT col_comment], ...)]
  [CLUSTERED BY (col_name, col_name, ...) [SORTED BY (col_name [ASC|DESC], ...)] INTO num_buckets BUCKETS]
  [SKEWED BY (col_name, col_name, ...)                  -- (Note: Available in Hive 0.10.0 and later)]
     ON ((col_value, col_value, ...), (col_value, col_value, ...), ...)
     [STORED AS DIRECTORIES]
  [
   [ROW FORMAT row_format] 
   [STORED AS file_format]
     | STORED BY 'storage.handler.class.name' [WITH SERDEPROPERTIES (...)]  -- (Note: Available in Hive 0.6.0 and later)
  ]
  [LOCATION hdfs_path]
  [TBLPROPERTIES (property_name=property_value, ...)]   -- (Note: Available in Hive 0.6.0 and later)
  [AS select_statement];   -- (Note: Available in Hive 0.5.0 and later; not supported for external tables)

列的名称,列的类型

CREATE TABLE emp(
empno int,
ename string,
job string,
mgr int,
hiredate string,
sal double,
comm double,
deptno int
) ROW FORMAT DELIMITED FIELDS TERMINATED BY ‘\t’;

Describe Table/View/Materialized View/Column

DESCRIBE [EXTENDED|FORMATTED] 
  table_name[.col_name ( [.field_name] | [.'$elem$'] | [.'$key$'] | [.'$value$'] )* ];
                                        -- (Note: Hive 1.x.x and 0.x.x only. See "Hive 2.0+: New Syntax" below)

hive (default2)> desc formatted emp;在工作中FORMATTED比EXTENDED用的多因为这样可以更加清晰的看出来表的结构

Rename Table

ALTER TABLE table_name RENAME TO new_table_name;

hive (default2)> ALTER TABLE emp rename to emp2;