Experts in Postgres and Open Source Infrastructure

The NOT NULL constraint ensures that the column accepts only non-null values. In Postgres, the CHECK constraint can be used as an alternative to the NOT NULL.

PostgreSQL offers a built-in mathematical function named ABS() that takes an expression as an argument and retrieves an absolute value for the specified number.

PostgreSQL offers several built-in math functions such as ROUND(), CEIL(), and FLOOR() to round a number up to specific decimal places.

PostgreSQL offers several commands to optimize, improve or maintain the health of a database, tables, etc., such as ANALYZE and VACUUM commands.

In Postgres, VACUUM is a command-line utility that vacates the space engaged by obsolete records, tuples, etc. It optimizes the performance of the Postgres databases, records, etc.

The MOD() function is one of the built-in mathematical functions in Postgres that perform the modulo operation on two numbers and retrieves the remainder.

PostgreSQL offers a convenient command named ANALYZE that collects the statistics about a database, table, or table’s columns for the query planner.

In PostgreSQL, column aliases are temporary alternative names assigned to columns. The aliases are temporary alternatives, so they exist temporarily during the query’s execution.

PostgreSQL offers several built-in functions to find duplicate rows/records from a table, such as ROW_NUMBER() and COUNT().

PostgreSQL doesn’t support the ISNULL function. To achieve the functionality of the ISNULL function in Postgres, COALESCE function and CASE expressions are used.