PostgreSQL Alter Table: Alter a table to drop a column from it
4. Write a SQL statement to drop the column city from 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) |
region_id | text |
Now execute the following statement.
Sample Solution:
Code:
ALTER TABLE locations
DROP city;
Output:
Now see the structure of the table locations after alteration.
Column | Type | Modifiers ----------------+-----------------------+----------- location_id | numeric(4,0) | street_address | character varying(40) | postal_code | character varying(12) | state_province | character varying(25) | country_id | character varying(2) | region_id | text |
The above result shows that there is no 'city' column; it has been dropped from the table locations.
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Previous: Write a SQL statement to change the data type of the column region_id to text in the table locations.
Next: Write a SQL statement to change the name of the column state_province to state, keeping the same size and data type and size
What is the difficulty level of this exercise?
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