Skip to main content

Syntax

Where from_item can be:

Parameters

Examples

DISTINCT clause

Here is an example of SELECT DISTINCT. This query will return only the unique combinations of first_name and last_name, eliminating any duplicate rows.
Here is an example of SELECT DISTINCT ON. The query returns the latest order for each unique customer_id. ORDER BY is used to ensure that the desired row, that is, the row with the latest order date, appears first; otherwise, the returned row will be unpredictable.

Example of using several clauses

Below are the tables within the same schema that we will be writing queries from. The table taxi_trips includes the columns id, distance, duration, and fare, where id identifies each unique trip.
The table taxi includes the columns taxi_id and trip_id, where trip_id and id in taxi_trips are matching fields.
The table company includes the columns company_id and taxi_id, where taxi_id and taxi_id in taxi are matching fields.
The following query returns the total distance and duration of trips that are beyond the initial charge ($2.50) of each taxi from the company “Yellow Taxi” and “FabCab”.