I want to query the database but only find out if there is at least one result or not. I am trying to minimize the cost for this transaction. What would the structure be in Rails to have the query be SELECT TOP or SELECT FIRST in SQL?

CodePudding user response：

You could try exists?

Person.exists?(5) # by primary key
Person.exists?(name: 'David')
Person.exists? # is there at least one row in the table?
Person.where(name: 'Spartacus', rating: 4).exists?
Person.active.exists? # if you have an "active" scope

Note that this limits the result set to 1 in the SQL query and the select clause is something like SELECT 1 AS one