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Education

This is the Education section of the Command Prompt Website. Here you will find blogs specifically about how to use Postgres and related technologies.

PostgreSQL ARRAY_PREPEND() Function

PostgreSQL provides a built-in ARRAY_PREPEND() function that is used to append an element at the start of an array. It accepts two arguments: an element and an array.

PostgreSQL UNION ALL Operator With Examples

In Postgres, the UNION ALL operator combines the result sets of two or more queries into one table, including the duplicate records.

How to Find Array Length in PostgreSQL?

In Postgres, the ARRAY_LENGTH() is used to find the array's length. The ARRAY_LENGTH() function finds the array’s length based on the requested dimension.

PostgreSQL DROP VIEW IF EXISTS

If a VIEW to be dropped doesn’t exist, then Postgres throws a VIEW doesn’t exist error. To rectify this error, the “IF EXISTS” option is used with the DROP VIEW statement.

VIEWS in PostgreSQL: CREATE VIEW, DROP VIEW, UPDATE VIEW

Postgres provides the “CREATE VIEW”, “CREATE OR REPLACE VIEW”, and “DROP VIEW” statements to create, update or drop a view from the database.

How to Use POWER() Function in PostgreSQL

The POWER() or POW() function accepts two numeric values as arguments and retrieves the first value raised to the power of the second value.

How to Sort Table Data BY Date in PostgreSQL

To sort the table’s data into a specific format, the ORDER BY clause is used in Postgres. Postgres users must use the ORDER BY clause on the DATE type column to sort the table data by date.

Alias in PostgreSQL With Examples

ALIASES are used in Postgres to provide a temporary name to the columns, tables, etc., while executing/writing Postgres queries.

How to Fix Column Does not Exist Exception/Error in PostgreSQL

In Postgres, the “column doesn’t exist” error occurs because of various reasons, such as the searched column doesn’t exist, typo mistakes, column alias being used incorrectly, etc.

How to Define an Auto Increment Primary Key in PostgreSQL

To define an auto-incremented primary key in Postgres, specify a column name followed by a pseudo data type named “SERIAL”, and then specify the PRIMARY KEY keyword.