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Sometimes we have to store the unique records in a table, such as an email address, employee id, etc. To achieve this purpose, the “UNIQUE” constraint is used in PostgreSQL. The UNIQUE constraint allows us to store the unique rows/records in a table.
This post will explain the working of the UNIQUE constraint through practical examples. So, let’s begin.
How Does UNIQUE Constraint Work in PostgreSQL?
Each time when you …
PostgreSQL offers a CAST operator that takes an expression and a data type and converts the given expression into the specified data type.
The DROP command throws an error if a table to be dropped doesn’t exist while “DROP IF EXISTS” shows a notice instead of throwing an error.
In Postgres, the SELECT DISTINCT clause fetches only unique values from a result set returned by a query. It retains only one row from a set of duplicated rows.
In PostgreSQL, the COALESCE() function handles the null values more efficiently. It accepts unlimited arguments and returns the first non-null argument.
PostgreSQL doesn’t provide a DATEADD function to add an interval to date time. However, you can achieve the same functionality using the “+” and “-” operators.
PostgreSQL provides various functions, such as LOWER(), INITCAP(), or UPPER(), to alter a string to lowercase, proper case, and uppercase, respectively.
PostgreSQL offers multiple date/time functions, such as CURRENT_DATE, NOW(), EXTRACT(), CURRENT_TIMESTAMP, etc. If we talk about the CURRENT_TIMESTAMP function, it retrieves the current date, time, and timezone when a transaction starts.
This write-up will present a thorough overview of the Postgres CURRENT_TIMESTAMP function with examples. So, let’s begin.
How to Use CURRENT_TIMESTAMP Function in PostgreSQL?
Firstly, let’s understand the syntax of the CURRENT_TIMESTAMP function:
CURRENT_TIMESTAMP(<precision>);
Here, “precision” is an optional …
In PostgreSQL, we can use the "DELETE USING" statement, subquery, or Postgres immediate table to delete duplicate rows from a table.
In PostgreSQL, the MIN() function retrieves a set's minimum value. Use the LEAST() function to get the minimum/least value from more than one column
