can Postgresql create an index on array length?

Question

I am working on a Rails app, that stores data in a Postgresql 9.4 database, the products table has a column images which is an array, I'd like to get the products that have no images, i.e. array_length(images) = 0. Is it possible to create an index on this condition? i.e on the length of the array.

it's of type array, it's a Postgresql non standard type, it just contains the urls of the images. not the images themselves. — Nafaa Boutefer
– Nafaa Boutefer, Commented Aug 10, 2016 at 19:40

Peter Eisentraut · Accepted Answer · 2016-08-10 18:39:41Z

2

Sure, you can create an expression index:

CREATE INDEX ON products ((array_length(images));

answered Aug 10, 2016 at 18:39

Peter Eisentraut

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Amir Raminfar Over a year ago

You should accept this answer if it works @NafaaBoutefer

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