Modify the names, columns and constraints of an existing table.
Syntax
| Code Block |
|---|
| language | sql |
|---|
| linenumbers | true |
|---|
|
ALTER TABLE [schema_name.]table_name
{
RENAME TO [schema_name.]table_name |
ADD COLUMN column_name data_type |
DROP COLUMN column_name |
ADD PRIMARY KEY (column_name) |
DROP PRIMARY KEY (column_name) |
DROP PARTITION FOR
{
(value[,...n]) |
(BETWEEN value AND value)
}
} |
Description
| Parameter | Details |
|---|
| ADD / DROP COLUMN | Adds or drops a column. When adding a column, all existing rows will have NULL value for the new column. |
| ADD / DROP PRIMARY KEY | Adds or drops a primary key column. A table can have one primary key column. Primary keys must contain unique values and cannot contain NULL values. |
| DROP PARTITION | To drop partitions, specify one or more column values for the partition key, or a range of values by using the BETWEEN clause. The partitions where the value exists, or that are within the given range, will be dropped.
|
| RENAME | Lets you change change the name/schema of an existing tabletable name or move the table to a different schema.
|
Examples
| Code Block |
|---|
| language | sql |
|---|
| linenumbers | true |
|---|
|
ALTER TABLE store_sales RENAME TO store_profits;
ALTER TABLE store_sales ADD PRIMARY KEY (ss_ticket_number);
ALTER TABLE store_sales DROP COLUMN ss_wholesale_cost;
ALTER TABLE web_events DROP PARTITION FOR ('2014-05-27');
ALTER TABLE web_events DROP PARTITION FOR (BETWEEN '2014-01-01' AND '2014-03-01'); |