Apache Drill - Querying Parquet Files
阿新 • • 發佈:2020-08-04
https://www.tutorialspoint.com/apache_drill/apache_drill_querying_parquet_files.htm
Parquet is a columnar storage format. Apache Drill uses Parquet format for easy, fast and efficient access.
Create a Table
Before moving to create a table in parquet, you must change the Drill storage format using the following command.
Query
0: jdbc:drill:zk = local> alter session set `store.format`= 'parquet';
Result
+-------+------------------------+ | ok | summary | +-------+------------------------+ | true | store.format updated. | +———----+------------------------+
You can create a table using the following syntax.
Query
0: jdbc:drill:zk = local> create table dfs.tmp.`/Users/../workspace` as select * from
dfs.`/Users/../workspace/Drill-samples/student_list.json`;
Result
+----------+---------------------------+ | Fragment | Number of records written | +----------+---------------------------+ | 0_0 | 10 | +----------+---------------------------+
To see the table contents, type-in the following query −
Query
0: jdbc:drill:zk = local> select * from dfs.tmp.`/Users/../workspace`;
Result
+-----+-------+-----+--------+----------+-------+-------+-------+-------------------+---------+ | ID | name | age | gender | standard | mark1 | mark2 | mark3 | addr | pincode | +-----+-------+-----+--------+----------+-------+-------+-------+-------------------+---------+ | 001 | Adam | 12 | male | six | 70 | 50 | 60 | 23 new street | 111222 | | 002 | Amit | 12 | male | six | 40 | 50 | 40 | 12 old street | 111222 | | 003 | Bob | 12 | male | six | 60 | 80 | 70 | 10 cross street | 111222 | | 004 | David | 12 | male | six | 50 | 70 | 70 | 15 express avenue | 111222 | | 005 | Esha | 12 | female | six | 70 | 60 | 65 | 20 garden street | 111222 | | 006 | Ganga | 12 | female | six | 100 | 95 | 98 | 25 north street | 111222 | | 007 | Jack | 13 | male | six | 55 | 45 | 45 | 2 park street | 111222 | | 008 | Leena | 12 | female | six | 90 | 85 | 95 | 24 south street | 111222 | | 009 | Mary | 13 | female | six | 75 | 85 | 90 | 5 west street | 111222 | | 010 | Peter | 13 | female | six | 80 | 85 | 88 | 16 park avenue | 111222 | +-----+-------+-----+--------+----------+-------+-------+-------+-------------------+---------+