hiveql

Similar to SHOW TABLES command, do we have any such command to list all databases created so far? This page mentions the command SHOW DATABASES . From the manual: SHOW (DATABASES|SCHEMAS) [LIKE identifier_with_wildcards]; SHOW DATABASES lists all of the databases defined in the metastore. The optional LIKE clause allows the list of databases to be filtered using a regular expression. Wildcards in the regular expression can only be '' for any character(s) or '|' for a choice. Examples are 'employees', 'emp', 'emp*|*ees', all of which will match the database named 'employees'. show databases;

I'm a noobie here. I'm trying to retrieve top 2 tables from my employee list based on salary in hive (version 0.11). Since it doesn't support TOP function, is there any alternatives? Or do we have define a UDF? Akshay Shrivastava Yes, here you can use LIMIT . You can try it by the below query: SELECT * FROM employee_list SORT BY salary DESC LIMIT 2 select * from employee_list order by salary desc limit 2; 来源： https://stackoverflow.com/questions/30441744/select-top-2-rows-in-hive

I need to move a hive table from one database to another. How can I do that? Since 0.14, you can use following statement to move table from one database to another in the same metastore: use old_database; alter table table_a rename to new_database.table_a The above statements will also move the table data on hdfs if table_a is a managed table. create external table new_db.table like old_db.table location '(path of file in hdfs file)'; if you have partition in table then you have to add partition in new_db.table. You can try - CTAS USE NEW_DB; CREATE TABLE table AS SELECT * FROM OLD_DB.table;

This page says of collect_list: Returns a list of objects with duplicates. Is that list ordered? For example, the order of the query results? built-in collect_list isn't guaranteed to be ordered, even if you do an order by first (even if it did ensure order, doing it this way is a waste of time). Just use brickhouse collect ; it ensures the elements are ordered. It's correct that collect_list isn't guaranteed to be ordered. The function sort_array will sort the result: select a, b, sort_array(collect_list(c)) as sorted_c from the_table group by a, b 来源： https://stackoverflow.com/questions

Referring to Hive2 created a simple java program to connect to HIVE2 server (not local) have added all mentioned jars in the above link in the class path in eclipse as well however when I run the code it throws an error as: 09:42:35,580 INFO Utils:285 - Supplied authorities: hdstg-c01-edge-03:20000 09:42:35,583 INFO Utils:372 - Resolved authority: hdstg-c01-edge-03:20000 09:42:35,656 INFO HiveConnection:189 - Will try to open client transport with JDBC Uri: jdbc:hive2://hdstg-c01-edge-03:20000 FAILED: f java.lang.NoSuchMethodError: org.apache.thrift.protocol.TProtocol.getScheme()Ljava/lang

The documentation of HIVE notes that LIMIT clause returns rows chosen at random . I have been running a SELECT table on a table with more than 800,000 records with LIMIT 1 , but it always return me the same record. I'm using the Shark distribution, and I am wondering whether this has got anything to do with this not expected behavior? Any thoughts would be appreciated. Thanks, Visakh Even though the documentation states it returns rows at random, it's not actually true. It returns "chosen rows at random" as it appears in the database without any where/order by clause. This means that it's not