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PostgreSQL Alter Table: Alter a table to add a new column


2. Write a SQL statement to add a column region_id to the table locations.

Here is the structure of the table locations.

postgres=# \d locations
     Column     |         Type          | Modifiers
----------------+-----------------------+-----------
 location_id    | numeric(4,0)          |
 street_address | character varying(40) |
 postal_code    | character varying(12) |
 city           | character varying(30) |
 state_province | character varying(25) |
 country_id     | character varying(2)  |

Now execute the following statement.

Sample Solution:

Code:

ALTER TABLE locations
ADD region_id  INT;

Output:

See the structure of the table after alteration.

postgres=# \d locations

     Column     |         Type          | M
----------------+-----------------------+--
 location_id    | numeric(4,0)          |
 street_address | character varying(40) |
 postal_code    | character varying(12) |
 city           | character varying(30) |
 state_province | character varying(25) |
 country_id     | character varying(2)  |
 region_id      | integer               |

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Next: Write a SQL statement to change the data type of the column region_id to text in the table locations.

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