Does Hive have something equivalent to DUAL?

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I'd like to run statements like

SELECT date_add('2008-12-31', 1) FROM DUAL

Does Hive (running on Amazon EMR) have something similar?

Not yet: https://issues.apache.org/jira/browse/HIVE-1558

Does Hive have something equivalent to DUAL?, Apache Hive DUAL Table Support and Alternative. Apache Hive like many other relational databases does not support dual table. You can simply use the SELECT without FROM clause to display the results of the function or expression that you are testing. There is no explicit dummy table in Hive. Taking the liberty to assume that you want to use it for testing functions etc. Prior to hive 0.13+ we needed to do something like this, [code]SELECT mytestfunction(123) FROM some_existing_random_table LIM

Best solution is not to mention table name.

select 1+1;

Gives the result 2. But poor Hive need to spawn map reduce to find this!

Apache Hive DUAL Table Support and Alternative, Prior to hive 0.13+ we needed to do something like this,. SELECT mytestfunction( 123) FROM some_existing_random_table LIMIT 1;. In this that existing table just � Hive Active Thermostat™ What is “Dual” mode? Dual automatically switches between heating and cooling based on your comfort zone. Simply set your heating and cooling target temperatures and your Hive Active Thermostat™ will keep your indoor temperature between these set points.

To create a dual like table in hive where there is one column and one row you can do the following:

create table dual (x int);
insert into table dual select count(*)+1 as x from dual;

Test an expression:

select split('3,2,1','\\,') as my_new_array from dual;

Output:

["3","2","1"]

Do we have a dummy table like Dual in Hive? If not, what will be the , I'd like to run statements like SELECT date_add('2008-12-31', 1) FROM DUAL Does Hive (running on Amazon EMR) have something similar? faking DUAL table in hive 04 Oct 2014. It is sometimes beneficial to have something constant in database. RDBMs engines like Oracle or DB2 have tables like DUAL or SYSIBM.SYSDUMMY1. In hive there is no such thing by default … But why not create a custom one? The easiest way (which I think works on all (???)

There is a nice working solution (well, workaround) available in the link, but it is slow as you might imagine.

The idea is that you create a table with a dummy field, create a text file whose content is just 'X', load that text into that table. Viola.

CREATE TABLE dual (dummy STRING);

load data local inpath '/path/to/textfile/dual.txt' overwrite into table dual;

SELECT date_add('2008-12-31', 1) from dual;

Does Hive have something equivalent to DUAL? - hadoop - iOS, Hive does not work with storage heaters or individual plug-in electric room heaters. Other systems - Our engineers do not install to solid fuel boilers (such as biomass systems, coal) and heat pumps. We haven’t tested on these systems, so can’t guarantee compatibility.

Quick Solution:

We can use existing table to achieve dual functionality by following query.

SELECT date_add('2008-12-31', 1) FROM <Any Existing Table> LIMIT 1

For example:

SELECT CONCAT('kbdjj','56454') AS a, null AS b FROM tbl_name LIMIT 1

Result

"limit 1" in query is used to avoid multiple occurrences of specified values (kbdjj56454,null).

SELECT ‘something’ I have to have DUAL table in SQL Server, what is the workaround? If you have transferred your code from Oracle and you do not want to remove DUAL yet, you can create a DUAL table yourself in the SQL Server and use it. Here is a quick script to do the said procedure. CREATE TABLE DUAL (DUMMY VARCHAR (1)) GO INSERT INTO

SerDe interface allow us to instruct hive as to how the record should be processed. Serializer will take java object that hive has been working on,and convert it into something that hive can store and Deserializer take binary representation of a record and translate into java object that hive can manipulate.

Hive doesn’t have the same integration with third-party products, but it does have its own growing range of Hive-branded smart home devices, including motion sensors and the new Active Lights.

Does Hive have something equivalent to DUAL? I'd like to run statements like SELECT date_add('2008-12-31', 1) FROM DUAL Does Hive (running on Amazon EMR) have something similar? hadoop hive amazon-emr

Comments
  • Most databases do not need a pseudotable like DUAL, thats Oracle only. So whats your real question, do you want to do date arithmetics?
  • @schlenk I just want something to run functions and do debugging from, since I'm not very familiar with the language.
  • This feature is now supported in hive
  • that issue was filed about 8 years ago and still not resolved... you can pretty much bet it never will be.
  • Not yet: hive> select 1 + 1; FAILED: ParseException line 1:14 mismatched input '<EOF>' expecting FROM near '1' in from clause
  • Old post but worth mentioning that this is supported in at least version 0.13
  • this is the simplest, and it works in scenarios where one doesn't have the rights to create a table.
  • SELECT CONCAT('kbdjj','56454') AS a, null AS b FROM (select * from tbl_name LIMIT 1) t. This query will be more efficient