How do I change the order of table columns in Hive?

2 years ago
Sophia Anderson
2 minutes

In Hive, the sequence of modifying table structure mainly includes adding, deleting, and modifying columns of the table. Below are specific steps for each operation:

  1. Change the structure of a table.
  2. Include additional columns.
  3. Name of the table
  4. fresh column
ALTER TABLE table_name ADD COLUMNS (new_column datatype);

Please replace datatype with the data type of the new column.

  1. Change the structure of a table
  2. Change columns
  3. The name of the table
  4. name of the column
ALTER TABLE table_name REPLACE COLUMNS (remaining_columns);

Please replace remaining_columns with all columns except the ones to be deleted.

  1. Changing columns: Since Hive does not directly support column modification, the usual approach is to create a new table, import the data from the old table into the new table, then delete the old table and rename the new table with the old table’s name. The specific steps are as follows:
    a. Create a new table, including the columns that need to be modified and other columns.
    b. Import the data from the old table into the new table.
    c. Delete the old table.
DROP TABLE table_name;

Rename the new table with the name of the old table.

ALTER TABLE new_table_name RENAME TO table_name;

Please make sure to back up the data in the table before performing the above operations to prevent any data loss.

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