Experts in Postgres and Open Source Infrastructure

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.

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

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.

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.

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

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

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.

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

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.

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.