PostgreSQL - incorrect syntax, when in condition is “false” value

Question

I have this scope in Rails:

  scope :by_default_checks, {:conditions => ['cars.sold IS ? AND cars.deactivated IS ?', nil, false]}

@cars = Car.by_title(params[:search][:title_like]).by_greater(params[:search][:amount_gte]).by_smaller(params[:search][:amount_lte]).by_default_checks

and on Heroku I am getting this error:

Completed 500 Internal Server Error in 6ms
... AND cars.sold IS NULL AND cars.deactivated IS 'f')
SELECT "cars".* FROM "cars"  WHERE (cars.title LIKE '%iphoe%') AND (cars.sold IS NULL AND cars.deactivated IS 'f')
PG::SyntaxError: ERROR:  syntax error at or near "'f'"

This code is working on SQLite, but doesn't on PostgreSQL. How to replace it?

Thanks

Answer 1

You should use = to check for equality with non-null values:

['cars.sold IS ? AND cars.deactivated = ?', nil, false]

You usually use is in is null , is not null , is distinct from , and is not distinct from when you're faced with NULLs and a simple = comparison will not work the way you want it to. You can use is for booleans if you're using the true or false values but not the 't' and 'f' strings that ActiveRecord uses to represent PostgreSQL booleans.

See Comparison Operators in the manual for details.

Alternatively, you could let ActiveRecord build the whole thing instead of using the old-school :conditions stuff:

scope :by_default_checks, where(:sold => nil).where(:deactivated => false)

That way ActiveRecord is responsible for all the native-to-PostgreSQL type conversions and it will choose the correct comparison operators for you.

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Also, developing on top of one database (SQLite) and deploying on another (PostgreSQL) is a really bad idea that will just lead to pain, suffering, and hair loss. There are all sorts of differences between databases that no ORM can insulate you from. Please fix this bug and then immediately switch your development environment to PostgreSQL.