目录
- PostgreSQL Tutorial
- Database
-
PostgreSQL Syntax
- PostgreSQL Operators
- PostgreSQL SELECT
- PostgreSQL
- PostgreSQL WHERE
- PostgreSQL ORDER BY
- PostgreSQL LIMIT
- PostgreSQL MIN and MAX
- PostgreSQL COUNT
- PostgreSQL SUM
- PostgreSQL AVG
- PostgreSQL LIKE
- PostgreSQL IN
- PostgreSQL BETWEEN
- PostgreSQL AS
- PostgreSQL Joins
- PostgreSQL INNER JOIN
- PostgreSQL LEFT JOIN
- PostgreSQL RIGHT JOIN
- PostgreSQL FULL JOIN
- PostgreSQL CROSS JOIN
- PostgreSQL UNION
- PostgreSQL GROUP BY
- PostgreSQL HAVING
- PostgreSQL EXISTS
- PostgreSQL ANY
- PostgreSQL ALL
- PostgreSQL CASE
- Exercises
PostgreSQL DROP COLUMN
The ALTER TABLE Statement
To remove a column from a table, we have to use the ALTER TABLE statement.
The ALTER TABLE statement is used to add, delete, or modify columns in an existing table.
The ALTER TABLE statement is also used to add and drop various constraints on an existing table.
DROP COLUMN
We want to remove the column named color from the cars table.
To remove a column, use the DROP COLUMN statement:
Example
Remove the color column:
ALTER TABLE cars
DROP COLUMN color;
Result
ALTER TABLE
Display Table
To check the result we can display the table with this SQL statement:
As you can see in the result, the color column has been removed from the cars table.
PostgreSQL Exercises
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