[ https://issues.apache.org/jira/browse/HIVE-178?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
David Phillips resolved HIVE-178. --------------------------------- Resolution: Fixed Fix Version/s: 0.13.0 {code} hive> select 1+1; OK 2 Time taken: 1.104 seconds, Fetched: 1 row(s) {code} > SELECT without FROM should assume a one-row table with no columns. > ------------------------------------------------------------------ > > Key: HIVE-178 > URL: https://issues.apache.org/jira/browse/HIVE-178 > Project: Hive > Issue Type: Wish > Components: Query Processor, Testing Infrastructure > Reporter: Adam Kramer > Priority: Minor > Labels: SQL > Fix For: 0.13.0 > > > SELECT 1+1; > should just return '2', but instead hive fails because no table is listed. > SELECT 1+1 FROM (empty table); > should also just return '2', but instead hive "succeeds" because there is "no > possible output," so it produces no output. > So, currently we have to run > SELECT 1+1 FROM (silly one-row dummy table); > ...which runs a whole mapreduce step to ignore a column of data that is > useless anyway. This is much easier due to local mode, but still, it would be > nice to be able to SELECT without specifying a table and to get one row of > output in moments instead of waiting for even a local-mode job to launch, > complete, and return. > This is especially useful for testing UDFs. > Relatedly, an optimization by which Hive can tell that data from a table > isn't even USED would be useful, because it means that the data needn't be > queried...the only relevant info from the table would be the number of rows > it has, which is available for free from the metastore. -- This message was sent by Atlassian JIRA (v6.3.4#6332)