SQLite check if a row exists

Question

I\'m trying to check if a specific ID exists in a table named \"Products\" in my sqlite database.

def existsCheck( db, id )
    temp = db.execute( \"select exist         


        

Answer 1

There is no need to use a subquery:

def existsCheck( db, id )
    db.execute( "select 1
                 from Products
                 where promoID = ?",
                [id] ).length > 0
end

This returns a boolean result.

Answer 2

Change it to:

def existsCheck( db, id )
    temp = db.execute( "select 1 where exists(
        select 1
        from Products
        where promoID = ?
    ) ", [id] ).any?
end

SQL query returns 1 when condition is met or empty result set if it's not. Whole function returns boolean depending on result set.