Postgres and Open Source Experts

The REVERSE() function accepts exactly one argument and that must be a string. As a result, it retrieves the given string in reverse order.

The STRING_TO_TABLE() function accepts a string and a delimiter as arguments and splits the given string based on the specified delimiter.

In PostgreSQL, the ORDER BY clause is used along with the COUNT() function to retrieve the table’s records by count/quantity.

In Postgres, a variable is declared with a particular data type, such as INTEGER, TEXT, DATE, etc. To declare a variable, use the “DECLARE var_name data_type:= expression;” syntax.

In PostgreSQL, comparison operators like greater than “>” and greater than or equal to “>=” can be used with the “CURRENT_DATE” function to get a date greater than or equal to today.

To copy a table from one database to another, open CMD as an administrator, and run the "pg_dump -U user –t table source_db | psql -U user target_db" command.

To install pgAdmin on Ubuntu, add the public key using Curl, add the pgAdmin repository using sudo, and execute the “sudo apt install pgAdmin4” command.

Execute the “sudo systemctl status postgresql” command to check the PostgreSQL service status on your Linux (Ubuntu) operating system.

Run the “\s” command from psql to get query history. To check the query history using pgAdmin, open the “query tool” and navigate to the “Query History” tab.

Postgres offers different built-in array functions that are used with the UPDATE command to modify an array, such as ARRAY_PREPEND(), ARRAY_REMOVE(), ARRAY_CAT(), etc.