# Hadoop Hive-specific SQL limitations

There are a few key limitations in Hive that prevent some regular Metadata Editor features from working as intended, and limit the structure of your SQL queries in Report Designer:

* Outer joins are not supported.
* Each column can only be used once in a `SELECT` clause. Duplicate columns in `SELECT` statements cause errors.
* Conditional joins can only use the = conditional unless you use a `WHERE` clause. Any non-equal conditional in a `FROM` statement forces the Metadata Editor to use a cartesian join and a `WHERE` clause conditional to limit it. This is not much of a limitation, but it may seem unusual to experienced Metadata Editor users who are accustomed to working with SQL databases.
* `INSERT` statements have a specific syntax and some limitations. Hive 0.14 supports insert statements with a specific syntax: `INSERT INTO TABLE tablename [PARTITION (partcol1[=val1], partcol2[=val2] ...)] VALUES values_row [, values_row ...]`. There are also some limitations surrounding use of the `INSERT` statement with the `SORTED` BY clause, non-support of literals for complex types, and the insertion of values into columns. For more details see:
  * <https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DML>
  * <https://cwiki.apache.org/confluence/display/Hive/Hive+Transactions>


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