SQL

碎片文件过多

sqly语句最后加上

distribute by ss_sold_date_sk, cast(rand() * 5 as int);

解析json文件并处理换行符

regexp_replace(get_json_object(json_content, '$.body'), '[\\n\\r]', '') as content

避免mapreduce

set hive.exce.mode.local.auto = true;

避免float错误

0.2对于float 类型是0.2000001，而对于double类型是0.200000000001

>cast(0.2 as float)

扫描一次数据

FROM history
  INSERT OVERWRITE sales SELECT * WHERE action='purchased'
  INSERT OVERWRITE credits SELECT * WHERE action='returned';

presto与hive的行列互转

concat_ws(',', collect_set(order_id))
array_join(array_distinct(array_agg(order_id)), ',')
lateral view explode(split(order_ids, ',')) b as order_id 
cross join unnest(split(order_ids, ',')) as b(order_id)

插入总行数

sum(1) over()

presto时间加减

date '$$begindate' - interval '2' day

将map类型合并

mapmerge(map(),paramcontext, factorcontext)