Postgres and Open Source Experts

In PostgreSQL, the CONCAT() function accepts multiple strings as arguments and concatenates them to a single string. Strings can be char, text, or varchar.

In PostgreSQL, the UNION clause/operator combines the result sets of two or more queries. It doesn’t return the duplicated rows in the combined set.

PostgreSQL provides a built-in function named the ROUND() function that accepts either one or two arguments/values. It rounds a number to the nearest integer.

Specify a string followed by “::” and then write the data type to convert the given string into the targeted type like integer, decimal, or double precision.

TO_NUMBER() is used to convert a character string to a number. The TO_NUMBER() function accepts two parameters, a “string” and a “format”.

In PostgreSQL, the BOOLEAN or BOOL data type takes only 1 byte to store a value in a database, and it returns one of two probable values: True or False.

BIGINT is a numeric data type in PostgreSQL that stores the integer values. It stores a value between -9,223,372,036,854,775,808 to +9,223,372,036,854,775,807.

In PostgreSQL, the CASCADE option is used with the DROP TABLE command to drop/delete a table along with its dependent objects.

To alter column’s type in PostgreSQL, use the “SET DATA TYPE” or “TYPE” keyword with the ALTER TABLE and ALTER COLUMN commands.

DATE_PART() function in PostgreSQL is used to extract/retrieve a specific part(like a month, year, hour, minutes, etc.) from a TIMESTAMP/Source.