10/19/2023 0 Comments Postgresql alter table drop column![]() Most of the ALTER TABLE operations work the same for internal tables PARTITION ( partition_spec) clause, you must includeĪll the partitioning columns in the specification. Whenever you specify partitions in an ALTER TABLE statement, through the Outside Impala, and bring them into the table using LOAD DATA or updatingĬomplex Types (Impala 2.3 or higher only) for details about using Remember that changing the file format for a table does not convert the dataįiles within the table you must prepare any Parquet data files containing complex types Or you can use ALTER TABLE SETįILEFORMAT to change the format of an existing table to Parquet so that ImpalaĬan query it. Type support in the ALTER TABLE statement applies to all file formats.įor example, you can use Impala to update metadata for a staging table in a non-Parquetįile format where the data is populated by Hive. You can use an ADD COLUMNS, DROP COLUMN, orĬHANGE clause to modify the table layout for complex type columns.Īlthough Impala queries only work for complex type columns in Parquet tables, the complex Statement can change the metadata for tables containing complex types In Impala 2.3 and higher, the ALTER TABLE Syntax: ALTER TABLE old_table_name RENAME TO new_table_nameĪLTER TABLE name ADD COLUMNS ( col_spec)ĪLTER TABLE name REPLACE COLUMNS ( col_spec)ĪLTER TABLE name ADD COLUMN col_specĪLTER TABLE name DROP column_nameĪLTER TABLE name CHANGE column_name col_spec ALTER TABLE name SET OWNER USER user_name - Kudu tables only.ĪLTER TABLE name ALTER column_name The data files to include extra fields, or converting them to a different file format. Typically need to perform corresponding physical filesystem operations, such as rewriting ![]() Moved to different paths.) When you do an ALTER TABLE operation, you RENAME TO clause is the one exception it can cause HDFS files to be Operations do not actually rewrite, move, and so on the actual data files. Metastore database that Impala shares with Hive. In Impala, this is primarily a logical operation that updates the table metadata in the ![]() The ALTER TABLE statement changes the structure or SQL Differences Between Impala and Hive.
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