CODEWITHSUNDEEP
postgresql
joslinm
joslinm

Reputation: 8105

Does PostgreSQL index null values?

If I have a table like so:

Food
-----------------
name | price | x

Let's say I create an index on name & price, but the database has a bunch of null values for both name & price in some of the rows. Does PostgreSQL automatically skip indexing those rows?

Upvotes: 10

Views: 7603

Answers (1)

Laurenz Albe
Laurenz Albe

Reputation: 247300

NULL values ARE indexed as well.

You can also use an index to speed up queries with a condition like

WHERE col IS NULL

Something that may come as a surprise to Oracle users is that you can have several rows with a NULL in a unique index. But that makes sense because NULL = NULL is not true.

Upvotes: 14

Related Questions