[大数据]利用mysql元数据自动生成hive建表语句

数仓搭建的过程中，需要将业务数据导入到hive中，但是业务表较多，建表成为一个效率瓶颈。可以利用mysql的元数据库INFORMATION_SCHEMA ,其中COLUMNS和 TABLES这两张表记录了我们需要的表名，列名，comemnt等信息。

下面是生产中实际用到的一个案例sql，在使用时可以根据自己公司的规范进行修改： 可以往where table name中添加多张表，实现批量创建

SELECT CONCAT('create table if not exists ods.ods_',schema_table, ' (',column_info,
              ') comment \'', TABLE_COMMENT, '\' partitioned by (p_date string) ROW FORMAT DELIMITED FIELDS TERMINATED BY \'\\001\' stored as orc',
            ' location \'hdfs://emr-cluster/user/hive/warehouse/fle_ods.db/ods_',schema_table, '\' TBLPROPERTIES ("orc.compress" = "snappy");')
FROM (SELECT TABLE_NAME,
             table_schema,
             schema_new,
             concat(schema_new,'_',TABLE_NAME,'','_di') as schema_table,
             TABLE_COMMENT,
             group_concat(CONCAT(COLUMN_NAME, ' ', DATA_TYPE, ' comment ', '\'', COLUMN_COMMENT, '\'')) AS column_info
      FROM (SELECT t1.TABLE_NAME,
                   t1.table_schema,
                   case when t1.table_schema ='test' then 'other_test' when t1.table_schema='order_test' then 'ods_order' else '??' end as schema_new,
                   t2.TABLE_COMMENT,
                   COLUMN_NAME,
                   CASE
                       WHEN DATA_TYPE = 'varchar' THEN 'string'
                       WHEN DATA_TYPE = 'int' THEN 'string'
                       WHEN DATA_TYPE = 'tinyint' THEN 'string'
                       WHEN DATA_TYPE = 'decimal' THEN 'string'
                       WHEN DATA_TYPE = 'datetime' THEN 'string'
                       WHEN DATA_TYPE = 'timestamp' THEN 'string'
                       WHEN DATA_TYPE = 'float' THEN 'string'
                       WHEN DATA_TYPE = 'double' THEN 'string'
                       when DATA_TYPE = 'bigint' THEN 'string'
                       WHEN DATA_TYPE = 'smallint' THEN 'string'
                       WHEN DATA_TYPE = 'tinyint' THEN 'string'
                       WHEN DATA_TYPE = 'date' THEN 'string'
                       WHEN DATA_TYPE = 'boolean' THEN 'string'
                       WHEN DATA_TYPE = 'time' THEN 'string'END AS DATA_TYPE,
                   COLUMN_COMMENT
            FROM COLUMNS t1
                     JOIN TABLES t2 ON t1.TABLE_NAME = t2.TABLE_NAME
            WHERE t1.TABLE_NAME in ('test_table_1','table_2')
           ) t3
      GROUP BY TABLE_NAME, TABLE_COMMENT
     ) t4