Impala数据库常用信息

1. 建表语句

• 带分区

CREATE TABLE gn_dm.dm_f_opty(
region_wid DOUBLE COMMENT '区域WID',   
employee_wid DOUBLE COMMENT '归属人WID',   
industry_wid DOUBLE COMMENT '行业WID',   
month_space_amount DOUBLE COMMENT '本月有效项目空间', 
w_insert_date TIMESTAMP ) 
PARTITIONED BY ( dt STRING ) ROW FORMAT DELIMITED FIELDS TERMINATED BY '\u0001' LINES TERMINATED BY '\n' 
WITH SERDEPROPERTIES ('field.delim'='\u0001', 'line.delim'='\n', 'serialization.format'='\u0001') 
STORED AS PARQUET LOCATION 'hdfs://nameservice1/GN/DM/DM_F_OPTY' 

2. 添加列（在最后添加）

ALTER TABLE tablename  add columns (name VARCHAR(8) comment'姓名');

3. 删除列

ALTER TABLE tablename  drop  name 

4. 删除分区

ALTER TABLE tablename drop if exists partition(dt = '20190520')
ALTER TABLE  tablename drop partition ( dt !='20201105')

5. 查询列的信息

DESCRIBE tablename

6. 查询建表语句

SHOW CREATE TABLE  tablename