VALUES clause for inline data in PostgreSQL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the VALUES clause do in SQL?

The VALUES clause lets you create a set of rows with specified data directly inside a query, without needing a table.

beginner

How do you write a simple VALUES clause with two rows of data?

Use VALUES followed by rows in parentheses, separated by commas. Example: VALUES (1, 'apple'), (2, 'banana')

intermediate

Can you use the VALUES clause as a table in a SELECT statement?

Yes, you can treat the VALUES clause like a temporary table and select from it using an alias.

intermediate

Why might you use the VALUES clause instead of creating a temporary table?

VALUES is quick and simple for small sets of data you want to use just once, without creating or managing a table.

intermediate

How do you assign column names to data from a VALUES clause?

Use an alias with column names after the VALUES clause. Example: VALUES (1, 'a') AS t(id, letter)

What keyword starts the inline data list in SQL?

A ROWS

B DATA

C VALUES

D INLINE

The VALUES keyword is used to start the inline data list.

How do you separate multiple rows in a VALUES clause?

A With semicolons (;)

B With periods (.)

C With colons (:)

D With commas (,)

Rows in a VALUES clause are separated by commas.

Which of these is a valid way to use VALUES in a SELECT?

A SELECT * FROM (VALUES (1, 'x'), (2, 'y')) AS t(id, letter)

B SELECT * FROM VALUES (1, 'x'), (2, 'y')

C VALUES SELECT (1, 'x'), (2, 'y')

D FROM VALUES (1, 'x'), (2, 'y') SELECT *

You must wrap VALUES in parentheses and give it an alias with column names to use in SELECT.

What is a good reason to use VALUES instead of a table?

A To quickly test or use small sets of data inline

B To store large amounts of data permanently

C To create indexes automatically

D To backup data

VALUES is best for quick, small inline data sets, not for permanent storage.

How do you name columns when using VALUES inline?

A Use AS with the VALUES keyword

B Use an alias with column names after VALUES in parentheses

C You cannot name columns in VALUES

D Use the COLUMN keyword

You assign column names by aliasing the VALUES clause with names in parentheses.

Explain how to use the VALUES clause to create inline data and select from it.

Think about how to write rows and give them names to use like a table.

Describe a situation where using the VALUES clause is better than creating a temporary table.

When you want to avoid extra setup and just use some data once.