In PostgreSQL, the FLOOR() function is used to round a numeric value down to the nearest integer that is less than or equal to the original value. The basic syntax of the FLOOR() function is as follows: FLOOR(numeric_expression) where numeric_expression is the numeric value or expression that you want to round down to the nearest…
In PostgreSQL, the CEIL() function is used to round a numeric value up to the nearest integer that is greater than or equal to the original value. It is also known as the “ceiling” function. The basic syntax of the CEIL() function is as follows: CEIL(numeric_expression) where numeric_expression is the numeric value or expression that…
In PostgreSQL, the ABS() function is used to compute the absolute value of a numeric or interval expression. The absolute value of a number is its magnitude without regard to its sign. If the number is positive or zero, the absolute value remains the same. If the number is negative, the absolute value is its…
You can drop a column from a table in PostgreSQL using the ALTER TABLE statement with the DROP COLUMN clause. Dropping a column will permanently remove the column and all its data from the table. Always backup your data before performing this operation. The basic syntax to drop a column is as below: ALTER TABLE…
In PostgreSQL, you can drop a table using the DROP TABLE statement. Dropping a table will permanently delete all the data and associated objects (such as indexes, triggers, and rules) related to that table. Make sure to take a backup of your data before executing the drop operation. The basic syntax to drop a table…
You can modify the datatype of a column in a table using the ALTER TABLE statement. However, changing the datatype of a column can lead to data loss or unexpected behavior if the new datatype cannot fully accommodate the existing data. Always, backup your data before making any changes. Below are the steps to modify…
An exclusion constraint is a type of constraint that allows you to specify a set of conditions that, if satisfied by any two rows in a table, will cause an error to be raised when trying to insert or update the table. Exclusion constraints are useful for preventing conflicts or overlaps between rows in a…
In PostgreSQL, a foreign key constraint is a type of constraint that is used to establish a relationship between two tables. The foreign key constraint ensures that the values in a column in one table correspond to the values in a column in another table. To create a foreign key constraint, you first need to…
In PostgreSQL, a primary key constraint is a way to enforce the uniqueness of a column or a group of columns in a table. A primary key constraint is created using the PRIMARY KEY keyword after the column or group of columns that you want to use as the primary key. For example, to create…
In PostgreSQL, the NOT NULL constraint is used to ensure that a column in a table does not contain any NULL values. If you attempt to insert a NULL value into a column with the NOT NULL constraint, PostgreSQL will raise an error and prevent the insertion. To apply the NOT NULL constraint to a…