Postgres and Open Source Experts

In Postgres, various tools, such as the “SQL Shell”, “pgAdmin”, and “Command Prompt” are used to connect to a Postgres database server.

In Postgres, the “-” operator and the AGE() function are used to find the date difference. The “-” operator returns an integer while the AGE() function returns an interval.

In PostgreSQL, use the RETURNING clause with the UPDATE, DELETE, or INSERT commands to return the modified rows.

In PostgreSQL, to get a timestamp without precision, users need to specify “0” as an argument to the timestamp data type or timestamp functions.

The SELECT statement is executed with the “*” symbol to select all data from a particular Postgres table. Use the ORDER BY clause with the SELECT * command to sort a table in a specific order.

To perform the date comparison in Postgres, the “BETWEEN” clause, the “DATE_TRUNC()” function, and the basic comparison operators like “=”, “!=”, “>=” etc., are used.

In PostgreSQL, the JSON_AGG() function is used to combine multiple values into a single JSON array. The return type of the JSON_AGG() function is JSON.

Postgres’ ALTER DATABASE command modifies the already existing databases, such as renaming a database, modifying the database attributes, changing the database ownership, etc.

To set Windows PATH for Postgres tools, open System Properties > “Environment Variable” > “Path” variable > “Edit..” button > “NEW” button > specify Postgres bin directory’s path > hit the “OK” button.

In Postgres, different commands, such as CREATE TABLE AS SELECT, CREATE TABLE AS TABLE, etc. are used to duplicate a table with or without data.