[ https://issues.apache.org/jira/browse/SPARK-19602?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16565802#comment-16565802 ]
Sunitha Kambhampati commented on SPARK-19602: --------------------------------------------- The design doc is also uploaded [here|https://drive.google.com/file/d/1zKm3aNZ3DpsqIuoMvRsf0kkDkXsAasxH/view] > Unable to query using the fully qualified column name of the form ( > <DBNAME>.<TABLENAME>.<COLUMNNAME>) > ------------------------------------------------------------------------------------------------------ > > Key: SPARK-19602 > URL: https://issues.apache.org/jira/browse/SPARK-19602 > Project: Spark > Issue Type: Improvement > Components: SQL > Affects Versions: 2.1.0 > Reporter: Sunitha Kambhampati > Assignee: Sunitha Kambhampati > Priority: Major > Attachments: Design_ColResolution_JIRA19602.pdf > > > 1) Spark SQL fails to analyze this query: select db1.t1.i1 from db1.t1, > db2.t1 > Most of the other database systems support this ( e.g DB2, Oracle, MySQL). > Note: In DB2, Oracle, the notion is of <schema>.<tablename>.<columnname> > 2) Another scenario where this fully qualified name is useful is as follows: > // current database is db1. > select t1.i1 from t1, db2.t1 > If the i1 column exists in both tables: db1.t1 and db2.t1, this will throw an > error during column resolution in the analyzer, as it is ambiguous. > Lets say the user intended to retrieve i1 from db1.t1 but in the example > db2.t1 only has i1 column. The query would still succeed instead of throwing > an error. > One way to avoid confusion would be to explicitly specify using the fully > qualified name db1.t1.i1 > For e.g: select db1.t1.i1 from t1, db2.t1 > Workarounds: > There is a workaround for these issues, which is to use an alias. -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org