'Ordering based on one value of many

I have three SQL tables. Users, Registration Field Values, and Registration Fields.

Name zip code favorite food
Sue 55555 sushi
Gary 12345 eggs

Where zip code and favorite food are different registration fields.

The relationship is a user has many registration field values, and those values belong to the registration field.

I'm wondering how I can order my table based on a certain registration field. For example, selecting "favorite food", I would want "eggs" before "sushi".

This is confusing to me because I've only seen ORDER BY for an individual column or series of columns. I can't just ORDER BY registration_field_value.value because it needs to be based on only one of those registration fields.

This is like "ORDER BY field value where the associated field id is 'favorite food'", although I don't want to filter anything out.

I'm using Postgres if that makes a difference.

EDIT, adding a diagram:

sqlpostgresql


Solution 1:[1]

You can use case to order based on specific value.

For eg:

ORDER BY
   CASE "favorite food"
      WHEN 'eggs' THEN 1
      ELSE 2
   END

The above query will move row with eggs to start and all other value will be moved to bottom.

Sources

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Source: Stack Overflow

Solution Source
Solution 1

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